Issue 24: Chemistry

Well. I admit I know many of my other classmates take Biology but I was placed in a chemistry class so this would help you ppl eventually~
Actually I don't mind if people give me theirs. All they should do is email me at yao6488@gmail.com
And tell me who should I put as the person who made it. It could be a fake name but Idc. It's not mine and I want to give credit. Also I'm sorry people. I don't take French anymore... I take Japanese now~ :# much to my own selfishness.
Well... Here I go...
 From the Chemistry Reference Tables Workbook by Topical Review Book Company:
1 mole (mol) is 6 x 10^23 atoms, molecules, or ions.
Polyatomic Ions: charged particles composed of two or more atoms. These are quite stable.
The halides are negative ions formed from Group 17 elements >> halogens
Soluble ionic substances (SALT) dissolved in water will conduce electricity >>>> eletrolytes
The notation:
(s) >>>>>> Solid
(aq)>>>>> Liquid
A solution is homogeneous since the solute is distributed uniformly throughout.
Homogenous means of same/similiar nature.
The dissolved solution can't be separated by filtration
The presence of solute raises the boiling point of the solvent and lowers the freezing point of the solvent.
Pressure has an effect on solubility of a solid in water. Increase pressure, the more soluble, less pressure less soluble.
The outermost energy level is the valence level as how many electrons in the valence level is the valence electron.
Any energy level higher than the ground state is referring to the excited stated.
When an excited atom returns to the ground state, energy is release in teh form of quanta, forming a bright line spectrum
To determine the # of neutrons in teh nucleus of an atom, subtract the atomic number from the mass number.
Electronegativity of an atom is the measure of the relative ability of that atom to attract bonding electrons to itself.
Atomic Radius is an estimate of the size of an atom or the distance from the center of the nucleus to the edge of the atom.

From the Barron's Let's Review Chemistry The physical setting and etc.

Neutrons add mass to an atom but do not change the atom's charge.
Isotopes:
A molecule is the smallest identifiable sample of a substance
The noble gases are isolated atoms and are monatomic molecules
Every molecule can be represented by a molecular formula which symbols of the element is succeeded by a subscript that indicates the number of atoms present.
The loss or gain or electrons by an atom results in the formation of an electrically charged particle called a ion.
Chemical formula is an important part of the language of chemistry because it tells us something about the composition of an element or a compound.
Binary Compound: exactly two elements. Ions in ionic compounds do not exist as individual molecules.
An ionic formula is the chemical formula for an ionic compound.
Molecular Formula: the number and type of atoms that are present in a single molecule of a substance.
Empirical Formula: the ratio of elements present in the compound.
Structural Formula: show how the atoms in a molecule are bonded to one another. This is usually to represent chemical bonds by lines and unshared pairs of electrons by a pair of dots.
Real Charges:
Apparent Charges:
Oxidation state: The oxidation number of every atom in a free element is 0. Free element meaning that an element is not combined with another element.
An atom becomes more stable when it acquires the electron configuration of a noble gas.If the valence level of a stabilized atom is the first principal energy level, it would contain TWO electrons, otherwise it will contain EIGHT electrons.
In MOST case, we say that the bonding atoms have obeyed the OCTET RULE.
Octet Rule: The octet rule is a bonding theory used to predict the molecular structure of covalently bonded molecules. Each atom will share, gain, or lose electrons in order to fill outer electron shells with eight electrons. For many elements, this rule works is quick and simple to predict the molecular structure of a molecule.
Read this for the exceptions: http://chemistry.about.com/od/chemicalbonding/tp/Exceptions-To-The-Octet-Rule.htm
Certain pairs of atoms do not have a strong tendency to transfer electrons between them. These atoms share electrons between them. Electron sharing always occurs in pair and the two atoms may normal share 1,2, or 3 pairs of electrons. The atoms bond together because the shared pair or pairs belong to both atoms. This is COVALENT BONDING.
However, the sharing of the electron pair is not always the same in both molecules. If the pairs of electrons are shared equally by both atoms. That is nonpolar covalent bonding. You can look at the structural formula. If it is symmetrical, it is nonpolar covalent.
If it isn't symmetrical it is polar covalent bonding. This is because the electrons are not shared equally.
The Lewis Dot structure is used to see which atoms are present AND how they are joined

That's all for now.