Curiosity Is A Door To New Dicoveries

Sunday, July 18, 2010

Oxidation State of an element

The oxidation state is an indicator of the degree of oxidation of an atom in a chemical compound.

The formal oxidation state is the hypothetical charge that an atom would have if all bonds to atoms of different elements were 100% ionic.

Oxidation states are typically represented by integers, which can be positive, negative, or zero. In some cases the average oxidation state of an element is a fraction, such as 8/3 for iron in magnetite (Fe₃O₄).

The highest oxidation state is +8 in the tetroxides of xenon, ruthenium and osmium, while the lowest is −4 for some elements in the carbon group.

The increase in oxidation state of an atom through a chemical reaction is known as an oxidation; a decrease in oxidation state is known as a reduction. Such reactions involve the formal transfer of electrons, a net gain in electrons being a reduction and a net loss of electrons being an oxidation. For pure elements, the oxidation state is zero.

Search engines: http://en.wikipedia.org/wiki/Oxidation_state

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Nuclear Weapons!

A nuclear weapon is an explosive device that derives its destructive force from nuclear reactions, either fission or a combination of fission and fusion. Both reactions release vast quantities of energy from relatively small amounts of matter; a modern thermonuclear weapon weighing little more than a thousand kilograms can produce an explosion comparable to the detonation of more than a billion kilograms of conventional high explosive.

Thus, even single small nuclear devices no larger than traditional bombs can devastate an entire city by blast, fire and radiation. Nuclear weapons are considered weapons of mass destruction, and their use and control has been a major focus of international relations policy since their debut.

Search engines: http://en.wikipedia.org/wiki/Nuclear_weapon

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Hydrogen Bomb!

Hydrogen bomb or H-bomb,weapon deriving a large portion of its energy from the nuclear fusion of hydrogen isotopes. In an atomic bomb, uranium or plutonium is split into lighter elements that together weigh less than the original atoms, the remainder of the mass appearing as energy.

Unlike this fission bomb, the hydrogen bomb functions by the fusion, or joining together, of lighter elements into heavier elements.

The end product again weighs less than its components, the difference once more appearing as energy. Because extremely high temperatures are required in order to initiate fusion reactions, the hydrogen bomb is also known as a thermonuclear bomb.

Search engines: http://www.infoplease.com/ce6/history/A0824719.html

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Orbital Theory

In chemistry, molecular orbital theory (MO theory) is a method for determining molecular structure in which electrons are not assigned to individual bonds between atoms, but are treated as moving under the influence of the nuclei in the whole molecule.In this theory, each molecule has a set of molecular orbitals.

Molecular orbital (MO) theory uses a linear combination of atomic orbitals (LCAO) to form molecular orbitals which cover the whole molecule. These are often divided into bonding orbitals, anti-bonding orbitals, and non-bonding orbitals.

A molecular orbital is merely a Schrödinger orbital which includes several, but often only two nuclei.

If this orbital is of type in which the electron(s) in the orbital have a higher probability of being between nuclei than elsewhere, the orbital will be a bonding orbital, and will tend to hold the nuclei together.

If the electrons tend to be present in a molecular orbital in which they spend more time elsewhere than between the nuclei, the orbital will function as an anti-bonding orbital and will actually weaken the bond.

Electrons in non-bonding orbitals tend to be in deep orbitals (nearly atomic orbitals) associated almost entirely with one nucleus or the other, and thus they spend equal time between nuclei or not. These electrons neither contribute nor detract from bond strength.

Molecular orbitals are further divided according to the types of atomic orbitals combining to form a bond. These orbitals are results of electron-nucleus interactions that are caused by the fundamental force of electromagnetism.

Chemical substances will form a bond if their orbitals become lower in energy when they interact with each other. Different chemical bonds are distinguished that differ by electron cloud shape and by energy levels.

MO theory provides a global, delocalized perspective on chemical bonding.

Search engines: http://en.wikipedia.org/wiki/Molecular_orbital_theory

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More Applications of Isotopes

Isotopes have different sets of properties. Their chemical properties do not vary while the physical properties may vary. Isotopes also exhibit different nuclear properties.

Applications Based on Physical and Chemical Properties

The physical properties of isotopes vary due to their nuclear structure but the chemical properties do not show much variance.

The popular uses based on these properties are discussed below.

Radio Isotopic Labeling

The use of isotopes is very common in Isotopic Labeling. Unusual isotopes are used as tracers or markers in chemical reactions. Atoms of an element generally cannot be distinguished from one another. These atoms can be distinguished using Mass Spectrometry or Infrared Spectroscopy, where isotopes of different masses are used. Radiations of radioactive isotopes can be used for detecting various reactants, rates, and so on in chemistry.

Radiometric Dating

Isotopes are used in Radiometric Dating, which is similar to Radio Isotopic Labeling or Radiocarbon Dating. Radiometric Dating is also used to study chemical processes by using naturally occurring isotopic tracers.

Isotopic Substitution

Isotopic substitution can be used to determine the mechanism of a reaction using Kinetic Isotope Effect.

Applications Based on Nuclear Properties

Isotopes exhibit different nuclear properties because they have varied numbers of neutrons. This also affects their physical properties.

Spectroscopy

Spectroscopy uses many unique nuclear properties of specific isotopes. For example, Nuclear Magnetic Resonance (NMR) spectroscopy can be used only for isotopes with a nonzero nuclear spin. Isotopes commonly used for NMR spectroscopy are 1H, 2D, 15N, 13C, and 31P.

Search engines: http://www.globalspec.com/reference/41771/203279/Applications-of-Isotopes

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Applications of Isotopes

1. Warfare
2. Archeological/geological dating
3. Small power generators for space vehicles and pacemakers
4. smoke alarms
5. radioactive tracers
6. chemical analysis
7. neutron activation analysis used to authenticate antiques and art
8. food preservation by killing bacteria

Search engines: http://www.public.asu.edu/~jpbirk/CHM-115_BLB/Chpt21/sld087.htm

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Isotopes

Isotopes are different types of atoms (nuclides) of the same chemical element, each having a different number of neutrons; the different possible versions of each element are called isotopes.

For example, the most common isotope of hydrogen has no neutrons at all; there's also a hydrogen isotope called deuterium, with one neutron, and another, tritium, with two neutrons.

Search engines: http://www.colorado.edu/physics/2000/isotopes/index.html

http://en.wikipedia.org/wiki/Isotope

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Wednesday, July 7, 2010

Tools to study Atoms:

1. Scanning Electron Microscope (SEM)

2. Scanning Tunneling Microscope (STM)

3. Atomic Force Microscope (AFM)

Applications:

1. Field of Nanotechnology

2. Medical

3. Quantum Computers

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Chemistry

1. Atoms & Molecules

2. Chemical Formulae & Equation

3. Acids & Alkalis

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