NXT Robots

Hello, I'm here again and with a new post: NXT ROBOTS!

The Lego Mindstorms NXT is a programmable robotics kit released by Lego in 2006. The main component in the kit is a brick-shaped computer called the NXT brick. It can take input from up to four sensors and control up to three motors. The brick has a 100x64 pixel LCD display and four buttons that can be used to navigate a user interface using menus. It also has a speaker and can play sound files at sampling rates up to 8 kHz.

NXT Robots are used to compete in a lot of different tournaments. There are sumo combats, rescue events, and a lot more!

Here I leave you an example of a sumo combat. The objective of this event is to kick out from the "Tatami" the opponent's robot. I hope you like it!

Computers



Now I`m going to talk about computers

A computer generally means a programmable machine. The two principal characteristics of a computer are: it responds to a specific set of instructions in a well-defined manner and it can execute a prerecorded list of instructions (a program).

Modern Computers Defined

Modern computers are electronic and digital. The actual machinery — wires, transistors, and circuits — is called hardware; the instructions and data are called software.

       

The Role of Linux in Datacenter Modernization: An IDC Whitepaper

Download Now

100%

All general-purpose computers require the following hardware components:

memory: enables a computer to store, at least temporarily, data and programs.

mass storage device: allows a computer to permanently retain large amounts of data. Common mass storage devices include disk drives and tape drives.

input device: usually a keyboard and mouse, the input device is the conduit through which data and instructions enter a computer.

output device: a display screen, printer, or other device that lets you see what the computer has accomplished.

central processing unit (CPU): the heart of the computer, this is the component that actually executes instructions.

In addition to these components, many others make it possible for the basic components to work together efficiently. For example, every computer requires a bus that transmits data from one part of the computer to another.

Computer Classification: By Size and Power

Computers can be generally classified by size and power as follows, though there is considerable overlap:

personal computer: a small, single-user computer based on a microprocessor. In addition to the microprocessor, a personal computer has a keyboard for entering data, a monitor for displaying information, and a storage device for saving data.

workstation: a powerful, single-user computer. A workstation is like a personal computer, but it has a more powerful microprocessor and a higher-quality monitor.

minicomputer: a multi-user computer capable of supporting from 10 to hundreds of users simultaneously.

mainframe: a powerful multi-user computer capable of supporting many hundreds or thousands of users simultaneously.

supercomputer: an extremely fast computer that can perform hundreds of millions of instructions per second.

Implants and Prosthetics

Today I`m going to talk about medical implants and prosthetics

 

Medical implants are devices or tissues that are placed inside or on the surface of the body. Many implants are prosthetics, intended to replace missing body parts. Other implants deliver medication, monitor body functions, or provide support to organs and tissues.

Some implants are made from skin, bone or other body tissues.  Others are made from metal, plastic, ceramic or other materials.

Implants can be placed permanently or they can be removed once they are no longer needed. For example, stents or hip implants are intended to be permanent.  But chemotherapy ports or screws to repair broken bones can be removed when they no longer needed.

The risks of medical implants include surgical risks during placement or removal, infection, and implant failure.  Some people also have reactions to the materials used in implants.

All surgical procedures have risks. These include bruising at the surgical site, pain, swelling and redness. When your implant is inserted or removed, you should expect these types of complications.

Infections are common.  Most come from skin contamination at the time of surgery. If you get an infection, you may need to have a drain inserted near the implant, take medication, or even have the implant removed.

Over time, your implant could move, break, or stop working properly.  If this happens, you may require additional surgery to repair or replace the implant.

If you learn that you need a medical implant, you should ask your doctor the following questions before agreeing to the procedure:

• Will my implant be permanent or removable? If the device is permanent, find out how long it should last. If the device is removable, find out how long it will be implanted in you and what factors will determine when it can come out.
• What material will the implant be made from? Make sure you are not allergic to any of the components in the implant.
• How many of these procedures have you done? The more experience a doctor has with inserting implants, the better the outcome may be.
• What are the complication rates from the procedure? Make sure you understand the risks of the surgery, infection, and device failure.
• What are the benefits of the procedure? Make sure you understand how the device will benefit you and if it will affect your quality of life.

Build your own workbench

A workbench is a very useful gadget to storage your tools and maintain them ordered.
Here I leave you a video for you to make your own workbench

Excel formulas

Have you ever had to use Excel and you have trouble with some complicated formulas?
Here I leave you a tutorial about Excel formulas
I hope you like it!

The same as before

I will say the same I say always: if you need any help with technology, post a comment in my newer post and I will help you with that ;)

How to make your own shelf

I´m here again (again). My new post, after a long time without posting nothing, will be a video of how to make your own shelf.
I hope you like it!

I´m here again!

Here you have a new post about internet safety. I hope you like it!

Precautions to take when meeting people face to face

As we get to know people online, there may be times when we want to meet them in person in the real world. It is extremely important that we take precautions before meeting face to face with someone online. Criminals and fraudsters can easily fake their identities and pretend to be someone else while online in order to lure victims into meeting with them in person.

you can also chat with a person on the phone before meeting in person, but be careful to block your caller ID or use an anonymous phone service like Skype. Never use your home phone or give out your phone number because this information can be used to identify and locate you.

Warning signs

Review the following tips to avoid running into trouble with people you meet face to face.

• 
  Trust your instincts, and pay attention when something doesn't feel right. Watch for "red flags" and questionable characteristics. Are the people you talk to controlling? Do they talk badly about others? Do they avoid certain questions? Are they quick to get mad? Your gut instincts are a good measure of whether you should proceed with someone or end things right away.
• Take your time, and maintain control. At any time if you feel uncomfortable, you have the right to walk away and end communications without any need to explain. Do not allow someone to persuade or badger you into moving forward before you are comfortable with doing so. If a person is genuine, he or she will understand your need to take things slowly.
• End things with someone who brings up "sex talk" too soon or asks about money. These people are almost always insincere and could end up scamming or harming you.
• Avoid drinking alcohol before or during your meeting, as this can impair your ability to judge another person and the safety of the circumstances
  .

More about robots

Here you have a video of construction robot helicopters

Robots

Today I´m going to talk about robots

A robot is a mechanical or virtual agent, usually an electro-mechanical machine that is guided by a computer program or electronic circuitry. Robots can be autonomous or semi-autonomous and range from humanoids such as Honda's Advanced Step in Innovative Mobility (ASIMO) and TOSY's TOSY Ping Pong Playing Robot (TOPIO) to industrial robots, collectively programmed 'swarm' robots, and even microscopic nano robots. By mimicking a lifelike appearance or automating movements, a robot may convey a sense of intelligence or thought of its own.
The branch of technology that deals with the design, construction, operation, and application of robots, as well as computer systems for their control, sensory feedback, and information processing is robotics. These technologies deal with automated machines that can take the place of humans in dangerous environments or manufacturing processes, or resemble humans in appearance, behavior, and/or cognition. Many of today's robots are inspired by nature contributing to the field of bio-inspired robotics. These robots have also created a newer branch of robotics: Soft robotics.
From the time of ancient civilization there have been many accounts of user-configurable automated devices and even automata resembling animals and humans, designed primarily as entertainment. As mechanical techniques developed through the Industrial age, their appeared more practical applications such as automated machines, remote-control and wireless remote-control. Electronics evolved into the driving force of development with the advent of the first electronic autonomous robots created by William Grey Walter in Bristol, England in 1948. The first digital and programmable robot was invented by George Devol in 1954 and was named the Unimate. It was sold to General Motors in 1961 where it was used to lift pieces of hot metal from die casting machines at the Inland Fisher Guide Plant in the West Trenton section of Ewing Township, New Jersey.
Robots have replaced humans in the assistance of performing those repetitive and dangerous tasks which humans prefer not to do, or are unable to do due to size limitations, or even those such as in outer space or at the bottom of the sea where humans could not survive the extreme environments.
There are concerns about the increasing use of robots and their role in society. Robots are blamed for rising unemployment as they replace workers in some functions. The use of robots in military combat raises ethical concerns. The possibility of robot autonomy and potential repercussions has been addressed in fiction and may be a realistic concern in the future.

                                

Plastic Creation Videos

Here I leave you some videos about how plastics are created

http://www.youtube.com/watch?feature=player_detailpage&v=6eCt0VDg-Kc

http://www.youtube.com/watch?feature=player_detailpage&v=T01i_vp2mJE

http://www.youtube.com/watch?feature=player_detailpage&v=8CfL5xl2N1Q

Electricity

Today I´m going to talk about electricity

Electricity is the set of physical phenomena associated with the presence and flow of electric charge. Electricity gives a wide variety of well-known effects, such as lightning, static electricity, electromagnetic induction and electrical current. In addition, electricity permits the creation and reception of electromagnetic radiation such as radio waves.
In electricity, charges produce electromagnetic fields which act on other charges. Electricity occurs due to several types of physics:

• electric charge: a property of some subatomic particles, which determines their electromagnetic interactions. Electrically charged matter is influenced by, and produces, electromagnetic fields.
• electric current: a movement or flow of electrically charged particles, typically measured in amperes.
• electric field (see electrostatics): an especially simple type of electromagnetic field produced by an electric charge even when it is not moving (i.e., there is no electric current). The electric field produces a force on other charges in its vicinity. Moving charges additionally produce a magnetic field.
• electric potential: the capacity of an electric field to do work on an electric charge, typically measured in volts.
• electromagnets: electrical currents generate magnetic fields, and changing magnetic fields generate electrical currents.

In electrical engineering, electricity is used for:

• electric power where electric current is used to energise equipment;
• electronics which deals with electrical circuits that involve active electrical components such as vacuum tubes, transistors, diodes and integrated circuits, and associated passive interconnection technologies.

Electrical phenomena have been studied since antiquity, though progress in theoretical understanding remained slow until the seventeenth and eighteenth centuries. Even then, practical applications for electricity were few, and it would not be until the late nineteenth century that engineers were able to put it to industrial and residential use. The rapid expansion in electrical technology at this time transformed industry and society. Electricity's extraordinary versatility means it can be put to an almost limitless set of applications which include transport, heating, lighting, communications, and computation. Electrical power is now the backbone of modern industrial society.

Plastics

Plastics are derived from organic products. The materials used in the production of plastics are natural products such as cellulose, coal, natural gas, salt and, of course, crude oil.

Crude oil is a complex mixture of thousands of compounds. To become useful, it must be processed.

The production of plastic begins with a distillation process in an oil refinery
The distillation process involves the separation of heavy crude oil into lighter groups called fractions. Each fraction is a mixture of hydrocarbon chains (chemical compounds made up of carbon and hydrogen), which differ in terms of the size and structure of their molecules. One of these fractions, naphtha, is the crucial element for the production of plastics.

The two major processes used to produce plastics are called polymerisation and polycondensation, and they both require specific catalysts. In a polymerisation reactor, monomers like ethylene and propylene are linked together to form long polymers chains. Each polymer has its own properties, structure and size depending on the various types of basic monomers used.

There are many different types of plastics, and they can be grouped into two main polymer families:

• Thermoplastics (which soften on heating and then harden again on cooling)
• Thermosets (which never soften when they have been moulded)

Examples of Thermoplastics Acrylonitrile butadiene styrene – ABS Polycarbonate - PC Polyethylene - PE Polyethylene terephthalate - PET Poly(vinyl chloride) - PVC Poly(methyl methacrylate) - PMMA Polypropylene - PP Polystyrene - PS Expanded Polystyrene - EPS

Examples of Thermosets Epoxide (EP) Phenol-formaldehyde (PF) Polyurethane (PUR) Polytetrafluoroethylene - PTFE Unsaturated polyester resins (UP)

Tantalum

Today I´m going to talk about tantalum

Tantalum is a greyish silver, heavy, and very hard metal. When pure, it is ductile and can be drawn into fine wire, which can be used as a filament for evaporating metals such as aluminium. Tantalum is almost completely immune to chemical attack at temperatures below 150°C, and is attacked only by hydrofluoric acid, acidic solutions containing the fluoride ion, and free sulphur trioxide. The element has a melting point exceeded only by tungsten and rhenium.

Table: basic information about and classifications of tantalum.

Name: Tantalum Symbol: Ta Atomic number: 73 Atomic weight: 180.94788 (2) Standard state: solid at 298 K CAS Registry ID: 7440-25-7

Group in periodic table: 5 Group name: (none) Period in periodic table: 6 Block in periodic table: d-block Colour: grey blue Classification: Metallic

 Small and large samples of tantalum wire like this, as well as foil, sheet, insulated wire, mesh and rod, can be purchased via their web catalogue from Advent Research Materials via their web catalogue.

Tantalum: historical information

Tantalum was discovered by Anders Ekeberg at 1802 in Sweden. Origin of name: from the Greek word "Tantalos" meaning "father of Niobe" (Greek mythology, (tantalum is closely related to niobium in the periodic table).

                                            

 

 

 

 

 

 

 

 

 

Niobium was discovered in 1802 by Anders Gustaf Ekeberg, but many chemists thought niobium and tantalum were one and the same. Some felt that perhaps tantalum was an allotrope of niobium. Later, Rose, in 1844, and Marignac, in 1866, showed that niobic and tantalic acids were two different acids.

The first relatively pure tantalum was produced by von Bolton in 1907.

Tantalum: physical properties

• Melting point: 3290 [or 3017 °C (5463 °F)] K
• Boiling point: 5731 [or 5458 °C (9856 °F)] K
• Density of solid: 16650 kg m^-3

 

Tantalum: orbital properties

• Ground state electron configuration:  [Xe].4f¹⁴.5d³.6s²
• Shell structure:  2.8.18.32.11.2
• Term symbol:   ⁴F_3/2
• Pauling electronegativity: 1.5 (Pauling units)
•  First ionisation energy: 761 kJ mol^-1
•  Second ionisation energy: 1500 kJ mol^-1

 

Isolation

Isolation: isolation of tantalum appears to be complicated. Tantalum minerals usually contain both niobium and tantalum. Since they are so similar chemically, it is difficult to separate them. Tantalum can be extracted from the ores by first fusing the ore with alkali, and then extracting the resultant mixture into hydrofluoric acid, HF. Current methodology involves the separation of tantalum from these acid solutions using a liquid-liquid extraction technique. In this process tantalum salts are extracted into the ketone MIBK (methyl isobutyl ketone, 4-methyl pentan-2-one). The niobium remains in the HF solution.

After conversion to the oxide, metallic tantalum can be made by reduction with sodium or carbon. Electrolysis of molten fluorides is also used.

Cobalt

Today I´m going to talk about cobalt

Cobalt is a brittle, hard, silver-grey transition metal with magnetic properties similar to those of iron (ferromagnetic). Cobalt is present in meteorites. Ore deposits are found in Zaire, Morocco and Canada. The isotope cobalt-60 (⁶⁰Co) is an artificially produced isotope used as a source of γ rays (its high energy radiation is useful for sterilisation in medicine and of foods). Cobalt salts colour glass a beautiful deep blue colour. Cobalt compounds are important catalysts in a number of industrial processes. Cobalt is required in small amounts for life and is the only metal found in vitamins (cobalt is the critical component of vitamin B₁₂.

Table: basic information about and classifications of cobalt.

Name: Cobalt Symbol: Co Atomic number: 27 Atomic weight: 58.933195 (5) Standard state: solid at 298 K CAS Registry ID: 7440-48-4

Group in periodic table: 9 Group name: (none) Period in periodic table: 4 Block in periodic table: d-block Colour: lustrous, metallic, greyish tinge Classification: Metallic

Cobalt: historical information

Cobalt was discovered by Georg Brandt at 1735 in Sweden. Origin of name: from the German word "kobald" meaning "goblin" or evil spirit.

                                    

 

 

 

 

 

 

 

 

 

Minerals containing cobalt were of value to the early civilisations of Egypt and Mesopotamia for colouring glass deep blue.

Cobalt was announced to be an element by Georg Brandt about 1739 (or possibly 1735). He had been trying to demonstrate that the blue colour of glass was because of a new element, cobalt, rather than bismuth, an element often found in the same locations as cobalt.

Cobalt: physical properties

• Melting point: 1768 [or 1495 °C (2723 °F)] K
• Boiling point: 3200 [or 2927 °C (5301 °F)] K
• Density of solid: 8900 kg m^-3

 

Cobalt: orbital properties

• Ground state electron configuration:  [Ar].3d⁷.4s²
• Shell structure:  2.8.15.2
• Term symbol:   ⁴F_9/2
• Pauling electronegativity: 1.88 (Pauling units)
•  First ionisation energy: 760.4 kJ mol^-1
•  Second ionisation energy: 1648 kJ mol^-1

 

Isolation

Isolation: it is not normally necessary to make cobalt in the laboratory as it is available readily commercially. Many ores contain cobalt but not many are of economic importance. These include the sulphides and arsenides linnaeite, Co₃S₄, cobaltite, CoAsS, and smaltite, CoAs₂. Industrially, however, it is normally produced as a byproduct from the produstion of copper, nickel, and lead.

Normally the ore is "roasted" to form a mixture of metals and metal oxides. Treatment with sulphuric acid leaves metallic copper as a residue and disolves out iron, cobalt, and nickel as the sulphates. Iron is obtained by precipitation with lime (CaO) while cobalt is produced as the hydroxide by precipitation with sodium hypochlorite (NaOCl)

2Co²⁺(aq) + NaOCl(aq) + 4OH^-(aq) + H₂O → 2Co(OH)₃(s) + NaCl(aq)

The trihydroxide Co(OH)₃ is heated to form the oxide and then reduced with carbon (as charcoal) to form cobalt metal.

2Co(OH)₃ (heat) → Co₂O₃ + 3H₂O

2Co₂O₃ + 3C → Co + 3CO₂

Zirconium

Today I´m going to talk about zirconium

Zirconium is a greyish-white lustrous metal. The finely divided metal can ignite spontaneously in air, especially at elevated temperatures. The solid metal is much more difficult to ignite. The inherent toxicity of zirconium compounds is low. Hafnium is invariably found in zirconium ores, and the separation is difficult. Commercial grade zirconium contains from 1 to 3% hafnium. The hafnium is removed from the zirconium used in the nuclear power industry.

Zirconium is found in S-type stars, and has been identified in the sun and meteorites. Analyses of lunar rock samples show a surprisingly high zirconium oxide content as compared with terrestrial rocks. Some forms of zircon (ZrSiO₄) have excellent gemstone qualities.

Table: basic information about and classifications of zirconium.

Name: Zirconium Symbol: Zr Atomic number: 40 Atomic weight: 91.224 (2) Standard state: solid at 298 K CAS Registry ID: 7440-67-7

Group in periodic table: 4 Group name: (none) Period in periodic table: 5 Block in periodic table: d-block Colour: silvery white Classification: Metallic

 Small and large samples of zirconium foil like this, as well as sheet and wire, can be purchased from Advent Research Materials via their web catalogue.

Zirconium: historical information

Zirconium was discovered by Martin Heinrich Klaproth at 1789 in Berlin, Germany. Origin of name: from the Arabic word "zargun" meaning "gold colour".

                                  

 

 

 

 

 

 

The name zircon probably originated from the arabic "zargun", which describes the colour of the gemstone now known as zircon (ZrSiO₄). The minerals jargon, hyacinth, and jacinth also contain zircon and these have been known since biblical times and are mentioned in the bible in several places. The existence of a new element within these minerals was not suspected until studies by Martin Heinrich Klaproth in the late 18th century.

The impure metal was first isolated by Jöns Jacob Berzelius in 1824 who heated a mixture of potassium and potassium zirconium fluoride together in an iron tube. Pure zirconium was first prepared in 1914.

Zirconium: physical properties

• Melting point: 2128 [or 1855 °C (3371 °F)]
• Boiling point: 4682 [or 4409 °C (7968 °F)] K
• Density of solid: 6511 kg m^-3

 

Zirconium: orbital properties

• Ground state electron configuration:  [Kr].4d².5s²
• Shell structure:  2.8.18.10.2
• Term symbol:   ³F₂
• Pauling electronegativity: 1.33 (Pauling units)
•  First ionisation energy: 640.1 kJ mol^-1
•  Second ionisation energy:  1270 kJ mol^-1

 

Isolation

Isolation: zirconium is available from commercial sources so preparation in the laboratory is not normally required. In industry, reduction of ores with carbon is not a useful option as intractable carbides are produced. As for titanium, the Kroll method is used for zirconium and involves the action of chlorine and carbon upon baddeleyite (ZrO₂). The resultant zirconium tetrachloride, ZrCl₄, is separated from the iron trichloride, FeCl₃, by fractional distillation. Finally ZrCl₄ is reduced to metallic zirconium by reduction with magnesium, Mg. Air is excluded so as to prevent contamination of the product with oxygen or nitrogen.

ZrO₂ + 2Cl₂ + 2C (900°C) → ZrCl₄ + 2CO

ZrCl₄ + 2Mg (1100°C) → 2MgCl₂ + Zr

Excess magensium and magnesium dichloride is removed from the product by treatment with water and hydrochloric acid to leave a zirconium "sponge". This can be melted under helium by electrical heating.

Iridium

Today I´m going to talk about iridium

Ruthenium, rhodium, palladium, osmium, iridium, and platinum together make up a group of elements referred to as the platinum group metals (PGM).

The name iridium is appropriate, for its salts are highly coloured. Iridium is white, similar to platinum, but with a slight yellowish cast. It is very hard and brittle, making it very hard to machine, form, or work. It is the most corrosion resistant metal known, and was used in making the standard metre bar of Paris, which is a 90% platinum-10% iridium alloy. This metre bar has since been replaced as a fundamental unit of length (see Krypton).
Iridium is not attacked by any of the acids nor by aqua regia, but is attacked by molten salts, such as NaCl and NaCN.

Table: basic information about and classifications of iridium.

Name: Iridium Symbol: Ir Atomic number: 77 Atomic weight: 192.217 (3) Standard state: solid at 298 K CAS Registry ID: 7439-88-5

Group in periodic table: 9 Group name: Precious metal or Platinum group metal Period in periodic table: 6 Block in periodic table: d-block Colour: silvery white Classification: Metallic

 Small and large samples of iridium foil like this, as well as wire, can be purchased via their web catalogue from Advent Research Materials via their web catalogue.

Iridium: historical information

Iridium was discovered by Smithson Tennant, Antoine Fourcroy, Louis Vanquelin, Hippolyte Collet-Descotils at 1803 in England, France. Origin of name: from the Greek word "iris" meaning "rainbow".

                                 

 

Osmium was discovered in 1803 by Smithson Tennant in the dark coloured residue left when crude platinum is dissolved by aqua regia (a mixture of hydrochloric and nitric acid). This dark residue contains both osmium and iridium (named after the Latin word iris meaning rainbow because of the colourful nature of iridium compounds).

Iridium: physical properties

• Melting point: 2739 [or 2466 °C (4471 °F)] K
• Boiling point: 4701 [or 4428 °C (8002 °F)] K
• Density of solid: 22650 kg m^-3

 

Iridium: orbital properties

• Ground state electron configuration:  [Xe].4f¹⁴.5d⁷.6s²
• Shell structure:  2.8.18.32.15.2
• Term symbol:   ⁴F_9/2
• Pauling electronegativity: 2.20 (Pauling units)
•  First ionisation energy: 880 kJ mol^-1
•  Second ionisation energy: 1600 kJ mol^-1

 

Isolation

Isolation: it would not normally be necessary to make a sample of iridium in the laboratory as the metal is available, at a price, commercially. The industrial extraction of iridium is complex as the metal occurs in ores mixed with other metals such as rhodium, palladium, silver, platinum, and gold. Sometimes extraction of the precious metals such as iridium, rhodium, platinum and palladium is the main focus of a partiular industrial operation while in other cases it is a byproduct. The extraction is complex because of the other metals present and only worthwhile since iridium is useful as a specialist metal and is the basis of some catalysts in industry.

Preliminary treatment of the ore or base metal byproduct is required to remove silver, gold, palladium, and platinum. The residue is melted with sodium bisulphate (NaHSO₄) and the resulting mixture extracted with water to give a solution containing rhodium sulphate, Rh₂(SO₄)₃. The insoluble residue contains the iridium. The residue is melted with Na₂O₂ and extracted into water to remove ruthenium and osmium salts. The residue contains iridium oxide, IrO₂. Dissolution of the oxide in regia (a mixture of hydrochloric acid, HCl, and nitric acid, HNO₃) gives a solution containing pure (NH₄)₃IrCl₆. Evaporation to dryness and burning under hydrogen gas gives pure iridium.

Yttrium

Today I´m going to talk about yttrium

Yttrium has a silvery-metallic lustre. Yttrium turnings ignite in air. Yttrium is found in most rare-earth minerals. Moon rocks contain yttrium and yttrium is used as a "phosphor" to produce the red colour in television screens.

Table: basic information about and classifications of yttrium.

Name: Yttrium Symbol: Y Atomic number: 39 Atomic weight: 88.90585 (2) Standard state: solid at 298 K CAS Registry ID: 7440-65-5

Group in periodic table: 3 Group name: (none) Period in periodic table: 5 Block in periodic table: d-block Colour: silvery white Classification: Metallic

Yttrium: historical information

Yttrium was discovered by Johann Gadolin at 1794 in Finland. Origin of name: named after the village of "Ytterby" near Vaxholm in Sweden.

                                     

 

 

Yttria (yttrium oxide, Y₂O₃), was discovered by Johann Gadolin in 1794 in a mineral called gadolinite from Ytterby. Ytterby is the site of a quarry in Sweden which contains many unusual minerals containing erbium, terbium, and ytterbium as well as yttrium. Friedrich Wohler obtained the impure element in 1828 by reduction of the anhydrous chloride (YCl₃) with potassium.

Yttrium: physical properties

• Melting point: 1799 [or 1526 °C (2779 °F)] K
• Boiling point: 3609 [or 3336 °C (6037 °F)] K
• Density of solid: 4472 kg m^-3

 

Yttrium: orbital properties

• Ground state electron configuration:  [Kr].4d¹.5s²
• Shell structure:  2.8.18.9.2
• Term symbol:   ²D_3/2
• Pauling electronegativity: 1.22 (Pauling units)
•  First ionisation energy: 600 kJ mol^-1
•  Second ionisation energy: 1180 kJ mol^-1

 

Isolation

Isolation: yttrium metal is available commercially so it is not normally necesary to make it in the laboratory. Yttrium is found in lathanoid minerals and the extraction of the yttrium and the lanthanoid metals from the ores is highly complex. Initially, the metals are extractedas salts from the ores by extraction with sulphuric acid (H₂SO₄), hydrochloric acid (HCl), and sodium hydroxide (NaOH). Modern purification techniques for these lanthanoid salt mixtures involve selective complexation techniques, solvent extractions, and ion exchange chromatography.

Pure yttrium is available through the reduction of YF₃ with calcium metal.

2YF₃ + 3Ca → 2Y + 3CaF₂

Mercury

Today I´m going to talk about mercury

Mercury is the only common metal liquid at ordinary temperatures. Mercury is sometimes called quicksilver. It rarely occurs free in nature and is found mainly in cinnabar ore (HgS) in Spain and Italy. It is a heavy, silvery-white liquid metal. It is a rather poor conductor of heat as compared with other metals but is a fair conductor of electricity. It alloys easily with many metals, such as gold, silver, and tin. These alloys are called amalgams. Its ease in amalgamating with gold is made use of in the recovery of gold from its ores.

The most important salts are mercuric chloride HgC1₂ (corrosive sublimate - a violent poison), mercurous chloride Hg₂Cl₂ (calomel, occasionally still used in medicine), mercury fulminate (Hg(ONC)₂, a detonator used in explosives), and mercuric sulphide (HgS, vermillion, a high-grade paint pigment).
Organic mercury compounds are important - and dangerous. Methyl mercury is a lethal pollutant found in rivers and lakes. The main source of pollution is industrial wastes settling to the river and lake bottoms.
As mercury is a very volatile element, dangerous levels are readily attained in air. Mercury vapour should not exceed 0.1 mg m^-3 in air. Air saturated with the vapour at 20°C contains mercury in a concentration far greater than that limit. The danger increases at higher temperatures. It is therefore important that mercury be handled with care. Containers of mercury should be securely covered and spillage should be avoided. Mercury should only be handled under in a well-ventilated area. If you are in possession of any mercury you are advised to contact a properly qualified chemist or public health laboratory for its safe disposal.
Small amounts of mercury spillage can be cleaned up by addition of sulphur powder. The resulting mixture should be disposed of carefully.

The result of burning ammonium dichromate, (NH₄)₂Cr₂O₇, containing pellets of mercuric thiocyanate (HgCNS). This is a large scale version of the indoor firework "Serpents in the grass" (only to be demonstrated by a professionally qualified chemist following a legally satisfactory hazard asessment). Improperly done, this reaction is dangerous! Llighting not great - sorry.

 

Table: basic information about and classifications of mercury.

Name: Mercury Symbol: Hg Atomic number: 80 Atomic weight: 200.59 (2) Standard state: liquid at 298 K (the heaviest known elemental liquid) CAS Registry ID: 7439-97-6

Group in periodic table: 12 Group name: (none) Period in periodic table: 6 Block in periodic table: d-block Colour: silvery white Classification: Metallic

Mercury: historical information

Mercury was discovered by Known since ancient times at no data in not known. Origin of name: named after the planet "Mercury" (the origin of the symbol Hg is the Latin word "hydrargyrum" meaning "liquid silver").

                                              

 

 

 

 

 

Mercury was known to ancient Chinese and Hindus before 2000 BC and was found in tubes in Egyptian tombs dated from 1500 BC It was used to forma amalgams of other metals around 500 BC. The Greeks used mercury in ointments and the Romans used it, unfortunately for those using it, in cosmetics.

Mercury is one of the elements which has an alchemical symbol, shown below (alchemy is an ancient pursuit concerned with, for instance, the transformation of other metals into gold).

Sometime prior to the autumn of 1803, the Englishman John Dalton was able to explain the results of some of his studies by assuming that matter is composed of atoms and that all samples of any given compound consist of the same combination of these atoms. Dalton also noted that in series of compounds, the ratios of the masses of the second element that combine with a given weight of the first element can be reduced to small whole numbers (the law of multiple proportions). This was further evidence for atoms. Dalton's theory of atoms was published by Thomas Thomson in the 3rd edition of his System of Chemistry in 1807 and in a paper about strontium oxalates published in the Philosophical Transactions. Dalton published these ideas himself in the following year in the New System of Chemical Philosophy. The symbol used by Dalton for mercury is shown below. [See History of Chemistry, Sir Edward Thorpe, volume 1, Watts & Co, London, 1914.]

 

Mercury: physical properties

• Melting point: 234.32 [or -38.83 °C (-37.89 °F)] K
• Boiling point: 629.88 [or 356.73 °C (674.11 °F)] K
• Density of solid: 14190 kg m^-3

 

Mercury: orbital properties

• Ground state electron configuration:  [Xe].4f¹⁴.5d¹⁰.6s²
• Shell structure:  2.8.18.32.18.2
• Term symbol:   ¹S₀
• Pauling electronegativity: 2.00 (Pauling units)
•  First ionisation energy: 1007.1 kJ mol^-1
•  Second ionisation energy: 1810 kJ mol^-1

 

Isolation

Isolation: the physical appearance of mercury is well known because of its use in many thermometers. It was common to demonstrate the formation of mercury in the laboratory by heating mercury sulphide (cinnabar, HgS) but this is strongly discouraged today because of the toxicity of mercury vapours. Don't do it! However, this method forms the basis of commercial extraction. The prepared cinnabar ore is heated in a current of air and the mercury vapour condensed.

HgS + O₂ (600°C) → Hg (l) + SO₂ (g)

The crude mercury is then washed with nitric acid and treated with air in order to remove impurities as oxides or into solution. Further purification is achieved by distillation at reduced pressure.