chemistry: CHAPTER 1

ATOM

STRUCTURE OF ATOM
According to the modern view, the atom consists of the core charge (+) and a cloud of charged electrons (-) caused electrons always move around the nucleus. Nuclei are of two types of piles constituent nucleons (particles making up the core) of protons and nucleons.

Development of Atomic Model
Atomic Model Dalton
In the year 1808, Jhon Dalton was a chemist developed as in England. He expressed his ideas about the atom is the smallest particle that can not be divided again. Dalton ideas put forward by the law of conservation of mass and definite proportions. The second, that the atoms are the same kind in every way, but the atoms are different elements of a type not different from other atoms. Furthermore the bond between the compound formed. And the atoms form a molecule with a number simple integer comparison.

Thomson's Atomic Model
Having found the atomic electron by Thomson, then Thomson compilede atomic model which is a refinement of Dalton's atomic model. Thomson atomic model suggests that in atoms the electrons are evenly distributed in the ball charge (+). And can be thought of as raisins scattered in all parts of the bread.

Rutherford atomic model

Atom consists of core electrons in the middle and then around it. Such statements similar to planets orbiting the sun. Rutherford did his experiments with α-rays fired into a thin metal plate.

Bohr Atomic Model
Bohr argued that atomic electrons surrounding the atomic nucleus on energy levels or a particular track.

ELEMENTS AND PERODIK system STRUCTURE ATOM

Periodic System of Elements
In the periodic system there are eight elements of a class A (main group) and delpan type B (type of transition) and the seventh period.
Here are eight main sections:

Group IA: alkali group.
Group IIA: alkaline earth group.
Group IIIA: boron groups.
Group IVA: carbon groups.
GroupsVA: group nitrogen.
Group VIA: oxygen groups.
Group VIIA: Halogens groups.
Group VIIIA: noble gas group.

Structure Atom
Basic particles making up an atom are electrons (-), protons (+), and neutrons (0).

Description:
Notation elements Z = atomic number = number of protons = number of electrons.
A notation elements = mass number = number of electrons.
A = number of neutrons (n) = A-Z

Negatively charged elements

atomic number = number of protons ≠ the number of electrons
The number of electrons = z + n

Positively charged element

atomic number = number of protons ≠ the number of electrons
The number of electrons = Z-n

Circulating Electron / Electron Structure
Electrons circulating in a certain trajectories called electron shells. The first skin was given the symbol K is the maximum 2 pieces of electrons. Klit both given a maximum of L symbols containing 8 pieces of electrons. The third skin is given the symbol F with a maximum of 18 pieces of electrons. The fourth skin containing 32 pieces of electrons. The skin contains the five symbols O 50 fruit electrons. Skin the maximum n (n) ² fruit electrons.
How to Charging Electrons In-Skin Leather

K - 2 / 1 / --
L - 8 / 7 / 6 / 5 / 4 / 3 / 2 / 1 / --
M - 18 /......./ 8 / 7 / 6 / 5 / 4 / 3 / 2 / 1 / --
N - 32 /................/ 8 / 7 / 6 / 5 / 4 / 3 / 2 / 1 / --
O - 50 /................../ 8 / 7 / 6 / 5 / 4 / 3 / 2 / 1 / --

Electrical Valence and Period
Valence electrons are electrons located atauout outer dikulit. As for the period indicated by the number of valence electrons to the skin.

Group IA
Group IIA
Group IIIA
Group IVA
Group VA
Group VIA
Group VIIA
Group VIIIA

Isotopes, Isobar, isoton
Isotopes
- It is the elements that have atomic numbers (Z) the same, while the mass number (A) is different
Example:
12C to 14C
6 6
Isobar
Are elements that have atomic numbers (Z) is different, whereas the mass number (A) the same.
Example:
14C to 14N
6 7
Isoton
Are elements that have nomo atoms (Z) and mass number (A) is different, but the same number of neutrons.
Example:

14C to 16O
6 8
Relative Atomic Mass (Ar) and the Relative Molecular Mass (Mr)
Relative Atomic Mass (Ar)
On the use of predetermined tahun 1961 isotope C-12 as a standard. Relative atomic mass of an element (Ar) which states adalhbilangan mass ratio is approximately one atomic element of 1 / 12 the mass of one atom of C-12 1 / 12 X C-12
Example:
The average mass of 1 atomic element is 2.66 X 10-23 grams if the mass of 1 atom C-12 is 1.99268 x 10-23 grams. Determine the atomic mass of element x is!
Answer
Ar element x = (average mass of 1 atom) / (1 / 12 the mass of the atom C-12)
= (2.66 X 〖10〗 ^ (-23)) / (1 / 12 1.99268 X 〖10〗 ^ (-23))
= 16.01862

Determining the Relative Atomic Mass (Ar) an isotope
Ar element x = Percent Abundance.
X 1 = time Ar x 1 +% abundance
X 2 = x Ar x 2 +
Example:
In Chloride element has 2 pieces of isotope isotopes 35Cl and 37Cl isotopes atomrelatifnya the mass (Ar) the results = 35.5 sma (atomic mass units)
Answer:
Cl-35: 75%
Cl-37: 25%
Ar Cl = (m1.p1 + m2.p2) / 100
= (35.75 +37.25) / 100
= 35.5 sma
Given:
Abundance 75 % Cl-35
Answer:
For example% abundance of Cl-35 = x%
% Abundance of Cl-37 = (100-x)%
Ar Cl = (% abundance of 35 Cl-Cl-Ar x 35) + (% abundance of 37 Cl-Cl-Ar x 37)
35.5 sma = (x% x 35 u) + ((100-x)% x 37 u)
35.5 sma = (35x +37 (100-x)) / 100
Sma = 35.5 (35x +3700-37 x) / 100
2x + 3550 = 3700 - 37x
2x = 150
X = 75

Relative Molecular mass (Mr)
The amount of the product between the number of its atoms with Ar.
Example:
H3PO4
Ba (NO3) 2
Given
Ar H = 1
Ar-P = 31
Ar O = 16
Ar Ba = 137
Ar-N = 14

Answer:
H3PO4 = (3 x H + P + 1 x 4 x O)
= (3 x 1 x 1 + 31 + 4 x 16)
= 3 + 31 + 64
= 98 sma

Ba (NO3) 2 = (1 + x Ba 2 x N + 6 x O)
= (137 + 1 x 2 x 6 x 14 + 16)
= 137 + 28 + 96
= 261 sma
Keperiodikan Element properties

Chemical formula
Is the molecular formula of a compound formed from the ions (+) cation ion (-) anion.
Kinds of ions (+) cations: