Click for money

Tuesday, January 21, 2014

Sodium Facts

Sodium Chemical & Physical Properties

 

Sodium
Sodium Basic Facts:
Symbol: Na
Atomic Number: 11
Atomic Weight: 22.989768
Element Classification: Alkali Metal
CAS Number: 7440-23-5
Sodium Periodic Table Location
Group: 1
Period: 3
Block: s
Sodium Electron Configuration
Short Form: [Ne]3s1
Long Form: 1s22s22p63s1
Shell Structure: 2 8 1
Sodium Discovery
Discovery Date: 1807
Discoverer: Sir Humphrey Davy [England]
Name: Sodium derives its name from the Medieval Latin 'sodanum' and the English name 'soda'. The element symbol, Na, was shortened from the Latin name 'Natrium'. Swedish chemist Berzelius was the first to use the symbol Na for sodium in his early periodic table.

Lithium Facts

Chemical & Physical Properties

Lithium
Atomic Number: 3
Symbol: Li
Atomic Weight: [6.938; 6.997]
Reference: IUPAC 2009
Discovery: 1817, Arfvedson (Sweden)
Electron Configuration: [He]2s1
Word Origin Greek: lithos, stone
Properties: Lithium has a melting point of 180.54°C, boiling point of 1342°C, specific gravity of 0.534 (20°C), and valence of 1. It is the lightest of the metals, with a density approximately half that of water. Under ordinary conditions, lithium is the least dense of the solid elements. It has the highest specific heat of any solid element. Metallic lithium is silvery in appearance. It reacts with water, but not as vigorously as does sodium. Lithium imparts a crimson color to flame, although the metal itself burns a bright white. Lithium is corrosive and requires special handling. Elemental lithium is extremely flammable.

Hydrogen Facts

Chemical & Physical Properties of Hydrogen

Hydrogen Atomic Number: 1
Hydrogen Symbol: H
Hydrogen Atomic Weight: [1.00784; 1.00811]
Reference: IUPAC 2009
Hydrogen Discovery: Cavendish, 1766. Hydrogen was prepared for many years before it was recognized as a distinct element.
Hydrogen Electron Configuration: 1s1






Hydrogen Word Origin: Greek: hydro, water; genes, forming Named by Lavoisier.
Hydrogen Isotopes: Protium (0 neutrons), Deuterium (1 neutron), and Tritium (2 neutrons)
Ground level: 2S1/2
Ionization potential: 13.5984 ev
Physical form: Colorless gas
Melting point: -259.2°C
Boiling point: -252.762°C
Critical temperature: -240.18°C
Density: 0.082 g/L
Specific heat: 14.304 J/g•K
Valence: 1
Hydrogen Properties: Hydrogen is the most abundant element in the universe. The heavier elements were made from hydrogen or from other elements that were made from hydrogen. Hydrogen is a colorless, odorless, combustible gas. Hydrogen gas is so light and diffusive that uncombined hydrogen can escape from the atmosphere. Hydrogen gas ordinarily is a mixture of two molecular forms, ortho- and para-hydrogen, which differ by the spins of their electrons and nuclei. Normal hydrogen at room temperature consists of 25% of the para form and 75% of the ortho form. The ortho form cannot be prepared in the pure state. Since the two forms of hydrogen differ in energy, their physical properties also differ.

This Day in Science History - January 21 - John Couch Adams

January 21th marks the passing of John Couch Adams. Adams was a British mathematician and astronomer who calculated the existence of a planet outside the orbit of Uranus to explain the irregularities of Uranus' orbit. He presented his calculations to the Cambridge Observatory, where they did nothing with the information. Meanwhile, a French mathematician named Urbain Le Verrier was doing the same calculations. He presented his results to Berlin Observatory's astronomer Johann Gottfried Galle, who quickly found Neptune within 1° of Le Verrier's prediction. When Berlin announced the discovery, Astronomer Royal George Airy remembered John Adams and his paper and tried to claim priority of the discovery. Both men are generally credited with the discovery today, but Le Verrier's actual published calculations and closer position is cited to give him the credit of discovery.

Why Glue Doesn't Stick to the Bottle

Have you ever wondered why glue doesn't stick to the inside of the glue bottle? Why not set up an experiment to see if you can figure out what glue needs in order to stick?

Some people think glue bottles are made from a special plastic that repels glue. This is easy to check. If you put a drop of glue on the bottle and allow it to dry, does it stick? Does it matter whether you try this on the inner or outer surface of the bottle?

Is it evaporation of the solvent, or is it something in air that makes glue sticky? It may be complicated to check every component of air, but you can easily prepare a gas that isn't air, to see what happens. For example, you could mix baking soda and vinegar or sublimate dry ice to make carbon dioxide gas. This gas is heavier than air, so you can fill a container with it. If you put a drop of glue inside the carbon dioxide to dry, the solvent will evaporate. Is that enough to make the glue sticky? Place an opened bottle of glue inside the carbon dioxide atmosphere. Does the glue stick to the bottle? Or, does the glue seem pretty much the same as before? What other processes might affect what makes glue sticky?

Monday, January 20, 2014

Periodic table Tips



Introduction to cell




This Day in Science History - January 20 - Alexandre-Emile Béguyer de Chancourtois

January 20th is the birthday of Alexandre-Emile Béguyer de Chancourtois. Béguyer de Chancourtois was a French geologist who was the first to organize the elements on a chart by increasing atomic weights. His graph was plotted on a cylinder where the circumference corresponded to 16 units, or the weight of oxygen. A spiral graph was wrapped around the cylinder where elements with similar chemical properties would line up vertically on the cylinder. This gave the impression of the properties of elements had recurring properties or "periodicity".

What Is Hydronium?

Hydronium

 Hydronium is what you get when you put water and hydrogen ions together, forming H3O+. Hydronium is the simplest form of oxonium, which is any ion that contains the trivalent oxygen cation. Hydronium is also known as hydroxonium. As with many species in chemistry, the nomenclature isn't the same everywhere.Where would you find hydronium? Hydronium is found in interstellar clouds and in the tails of comets. Interstellar hydronium probably forms as a result of chemical reactions following the ionization of H2 into H2+. Research is ongoing to elucidate the nature of the reactions

About Buckyballs

This round molecule is a buckyball. Can you believe it occurs naturally? Buckyballs are so interesting that they were named the 1991 Molecule of the Year by Science Magazine. How much do you know about them? I've got a multiple choice quiz so you can test your knowledge... Bring it on!

Learn togather in chemistry

Learn Together
Supplemental Instruction offers review sessions each week. Get together with your classmates to compare notes, discuss concepts, develop study strategies,

Eclectic Bedroom Design Ideas

One of the most popular bedroom design ideas is the eclectic style. It combines various styles to create a vivid and interesting room. The combination may incorporate vintage furniture, but use modern art or accents to create contrast. This style is sometimes sub-categorized under contemporary or modern styles by designers and other professionals, but in the end, this is the most popular style because it is fun, universal, diverse, and easy to achieve. Here are six tips to help you create an eclectic bedroom design, while maintaining balance and charm.

How to Design a Bedroom for Better Sleep

The bedroom can serve as a multifunctional room--such as an office, library, or laundry room--but in the end, it is a sanctuary for sleep. This room should be the most luxurious and personal space in any home - a soothing oasis that is conducive to relaxation and comfort. Here are some tips on how you can design your bedroom for better sleep, which should be considered along with color options, styles, and furniture.

1. A good mattress is the key to a good night’s rest. A good night's rest may be as simple as getting a new mattress. If your mattress is too lumpy, hard, or soft, it will keep you up all night trying to get comfortable. There are many different types of mattresses, such as pillow, foam, innerspring, adjustable, waterbeds, and airbeds; each type has manufacturers who guarantee comfort and better sleep. When you shop for a mattress, follow these simple steps:
 •Research extensively, because this is a very important and expensive purchase.
•Once you have a mattress in mind, test out your mattress. If your mattress has a 30 or 60 day guarantee or your money back, take advantage of it. Also, don't be afraid to try out a mattress in the store by lying down on it like you would at home.
•Figure out what size you need (King, Queen, or Full), because this may be the reason you cannot sleep; a small mattress may be your issue, especially if you share a bed. To determine if you need a new a mattress, these simple guidelines from The Better Sleep Council can help you make that determination.

Sunday, January 19, 2014

This Day in Science History - January 19 - Benzene Nomenclature

January 20th marks the passing of Carl Gräbe. Gräbe was a German organic chemist who discovered a method to synthesize the distinctive red alizarin dye with Carl Liebermann. This discovery greatly reduced the cost of the red dye that was previously only available from the madder plant.

Gräbe was also the chemist who introduced the nomenclature used to describe bond locations on benzene rings. Benzene is a ring of carbon atoms forming a hexagon. When two functional groups attach themselves to different points of the hexagon, different prefixes are used to differentiate different patterns. Gräbe introduced the use of the prefixes para-, meta-, and ortho- to the organic chemist's dictionary. The para- prefix indicates the functional groups are attached on opposite carbon atoms. Meta- is used to indicate when there is a one carbon atom gap between functional groups. Ortho- is used when two functional groups are on adjacent carbon atoms.

Definition of a Molecule and mole

Definition of a Molecule

Molecules are formed when two or more atoms are held together by chemical bonds.

Molecules Formed by Covalent Bonds

For example, the oxygen molecule consists of two atoms of oxygen. In the case of oxygen, the bond that holds the two atoms together is known as a covalent bond, and here is how it works.
The oxygen atom has 8 each of protons, neutrons, and electrons. The protons and neutrons are found in the center of the atom, known as the nucleus, and the electrons surround the nucleus in layers, or shells. The oxygen atom has 2 electrons in its first shell, and 6 in its second and outer shell. However, in chemistry, there exists the octet rule, which states that atoms generally strive to have 8 electrons in their outer shell. The oxygen therefore is 2 electrons away from a complete outer shell. When it binds with another oxygen atom, they can share two pairs of electrons and so each will have 8. When atoms share electrons like that, they form a molecule through a covalent bond.

Molecules Formed by Ionic Bonds

Molecules can also be formed through other kinds of chemical bonds, for example, an ionic bond. An example this is sodium chloride, or table salt. In an ionic bond, one atom has a much greater ability to attract electrons than the other atom. In this case, the chlorine, which is only 1 electron short of a complete outer shell, will steal that electron from the sodium, which has only 1 outermost electron. This turns the sodium into a positively charged ion, and the chlorine into a negatively charged ion, and the two atoms end up being held together by an electrostatic charge.

Meaning of a Mole

Now what is a mole? A mole is simply a counting number, much like a dozen. When we say "dozen", we mean 12; well, when we say "a mole" we mean 6.022 x 10 to the 23. Moles make it easier to quantify chemical substances. The periodic table lists the weights of all the elements in grams per mole.

Examples of Finding Molar Mass

For example, oxygen has molar mass of 16, which means 6.022 x 10 to the 23 atoms of oxygen weigh 16 grams. Hydrogen has a molar mass of 1. To find out the molar mass of a molecule, such as water, we need to add up the molar masses of the atoms it is composed of. Since water has two atoms of hydrogen and 1 atom of oxygen, its molar mass is 18 grams per mole.

Learn About Chemical Reaction

What Are Types of Chemical Reactions

Beryllium Facts

Chemical & Physical Properties

Beryllium
Atomic Number: 4
Symbol: Be
Atomic Weight: 9.012182(3)
Reference: IUPAC 2009
Discovery: 1798, Louis-Nicholas Vauquelin (France)
Electron Configuration: [He]2s2


Other Names: Glucinium or Glucinum
Word Origin: Greek: beryllos, beryl; Greek: glykys, sweet (note that beryllium is toxic)

Properties: Beryllium has a melting point of 1287+/-5°C, boiling point of 2970°C, specific gravity of 1.848 (20°C), and valence of 2. The metal is steel-gray in color, very light, with one of the highest melting points of the light metals. Its modulus of elasticity is a third higher than that of steel. Beryllium has high thermal conductivity, is nonmagnetic, and resists attack by concentrated nitric acid. Beryllium resists oxidation in air at ordinary temperatures. The metal has a high permeability to x-radiation. When bombarded by alpha particles, it yields neutrons in the ratio of approximately 30 million neutrons per million alpha particles. Beryllium and its compounds are toxic and should not be tasted to verify the metal's sweetness.

Calcium Facts

Chemical & Physical Properties of Calcium

 Calcium

Calcium Basic Facts:
Symbol: Ca
Atomic Number: 20
Atomic Weight: 40.078
Classification: Alkaline Earth
CAS Number: 7440-701-2
Calcium Periodic Table Location
Group: 2
Period: 4
Block: s
Calcium Electron Configuration
Short Form: [Ar]4s2
Long Form: 1s22s22p63s23p64s2


 

Shell Structure: 2 8 8 2
Calcium Discovery
Discovery Date: 1808
Discoverer: Sir Humphrey Davy [England]
Name: Calcium derives its name from the Latin 'calcis' which was the word for lime (calcium oxide, CaO) and limestone (calcium carbonate, CaCO3)
History: The Romans prepared lime in the first century, but the metal was not discovered until 1808. Swedish chemist Berzelius and Swedish court physician Pontin created an amalgam of calcium and mercury by electrolyzing lime and mercury oxide. Davy managed to isolate pure calcium metal from their amalgam.

Magnesium Facts

Chemical & Physical Properties

Magnesium
Atomic Number: 12
Symbol: Mg
Atomic Weight: 24.305
Discovery: Recognized as an element by Black 1775; Isolated by Sir Humphrey Davy 1808 (England)
Electron Configuration: [Ne] 3s2
Word Origin: Magnesia, a district in Thessaly, Greece
Properties: Magnesium has a melting point of 648.8°C, boiling point of 1090°C, specific gravity of 1.738 (20°C), and valence of 2. Magnesium metal is light (one-third lighter than aluminum), silvery-white, and relatively tough. The metal tarnishes slightly in air. Finely divided magnesium ignites upon heating in air, burning with a bright white flame.

Properties of vanderwals


Scientific Method Quiz

The scientific method is an objective way to explore the world around us. It is a systematic means of asking and answering questions, used by both scientists and non-scientists, all over the world. By the end of this quiz, you should feel confident you know the order of the steps of the scientific method and the difference between the three types of variables you may encounter in an experiment... Take the quiz

Element Word Search

Have you ever wanted to complete a word search containing the elements? Now you can fulfill that wish with the Element Word Search.

অধ্যায় - ৫ রাসায়নিক বন্ধন

অধ্যায় - ৫ রাসায়নিক বন্ধন ১. কোন গ্রুপের অধাতু আয়নিক বন্ধন গঠন করে? ক) ১৩ ও ১৬ খ) ১৫ ও ১৭ গ) ১৬ ও ১৭ ঘ) ১৭ ও ১৮ সঠিক উত্তর:...

Popular posts