1. CHAPTER 1 PERIODIC SYSTEM OF THE ELEMENTS AND ATOMIC STRUCTURE
Sistem Periodik Unsur dan Struktur Atom

2. Teaching Learning Objectives
The student can explain of Dalton’s atomic theory.
The student can explain of Thomson’s atomic theory.
The student can explain of Rutherford’s atomic theory.
The student can explain of Neils Bohr’s atomic theory.

3. A. Model and Theory of Atom
Democritus’ Atomic Theory
According to Democritus, if a stone divided, and we did that repeatedly until it is undivided any more, every pieces of that stone had the same character with its origin.
He labeled the smallest piece of stone as atomos (A=no, TOMos=divided), which mean
“invisible”. Based on his theory, every atom that constructed different matter is dissimilar.

4. The Greek Model
Democritus - A Greek Philosopher around the year 400 BC.
Democritus concluded that matter could not be divided into smaller and smaller pieces forever.
Eventually, the smallest piece of matter would be found. He used the word "Atomos" to describe the smallest possible piece of matter.

5. ATOMIC THEORY OF DALTON
A substance consist of minute particles that can’t be divided, and this is called an atom with a small massive ball shape
Atoms of an element are identical but they are different from atoms of the other elements
Chemically, atoms are interwoven to each other to perform a molecule with a simple comparison
A compound is the product of the reaction of atom
An atom of an element is permanent, can’t de divided or created or destroyed
Atom model of Dalton

6. 2. Dalton’s Atomic Theory and Model
Dalton suggested as followed :
Atom is the smallest particle of matter
Atom is small sizes and round-shaped, indivisible, neither created nor destoyed.
All atoms of given element are identical
Atoms of different element can be joined to produce substance with fixed scale.
Atoms combine to make compounds: a given compound always has the same relative number and kind of atoms

7. 3. Thomson’s Atomic Theory and Model
Whithin the experiment, by use of the cathode ray discovered by Thomson soon called as electron.
Based on this founding, Thomson suggested his atomic model, known as Plum-pudding.
Thomson argued that atom was ball-shapped with positive charge, and its negative charge electrons were spread inside the ball.
He pictured the small electrons to be embedded in the atom much like raisins in a pudding.

8. 4. Rutherford’s Atomic Theory and Model
Berdasarkan percobaan penembakan partikel ∂ pada lempeng emas yang sangant tipis,
Rutherford deduced as follow:
1. Atom is built from positively charged nucleus
and negatively charged electron around the
atoms nucleus.
2. Atom is neutral charge, so that the positive
particle (proton) and negative particle
(electron) have the same amount.

9. 5. Bohr’s Model and Atomic Theory
Bohr’s atomic theory can be comprehended as
follow;
Electrons are moving around nucleus in discreet level of energy.
Electrons may tranfer from one energy level to another energy level,
1. From low energy to upper level is called
excitation, and it absorbs energy,
2. From high energy to upper level is called
de-excitation, and it releases energy.

10. PARTIKEL DASAR ATOM Partikel Atom Lambang Massa Muatan Penemu gram sma
Coulomb
Pembu
lat an
Proton
Neutron
Elektron
11p
10 n
0-1e
1,67 x 10-24
9,11 x 10-28
1,007276
1,008665
0,000548
+1,602x10-19
-1,602x10-19 +1 -1
Goldstein
Chadwick
Thomson

11. B. Application of Chemical Element Periodic Table
Calculate the Amount of Proton, Electron and Neutron of Atom
X : atom or elements symbol
AzX
A : mass number= the total amount of proton and
neutron
Z : atomic number = the amount of proton

12. 2311 Na 2311 Na+ Example : Atom Na is neutral atom
Atomic number = z = 11 = proton number = electron number
Mass number = A= 23 = proton + neutron number
Neutron number = 23 – 11 = 12
2311 Na+
Atom Na+ is positive ion
Atomic number = z = 11 = proton number
Mass number = A= 23 = proton + neutron number
Neutron number = 23 – 11 = 12
Electron number = Z – charge = 11 – (+1) = 10

13. Isotop, Isobar, Isoton
Isotop adalah atom-atom sejenis yang memiliki Z sama A berbeda
Contoh : 166O, 176O dan 186O
Isobar adalah atom-atom yang memiliki A sama Z berbeda.
Contoh : 2411Na dan 2412Mg
Isoton adalah atom-atom yang memiliki jumlah
netron sama.
Contoh : 2311Na dan 2412Mg

14. 2. Electron Configuration
Electron Configuration is construction of electron in atom shells
The maximum amount in every shell is 2n2
Shell (n)
Max Electron
Number (2n2) 1 2 3 4 8 18 32

15. Atomic Electron Configuration
Element
Atomic Shell
Valence
Electron K L M N O P Q
3Li 2 1 1 9F 2 7 7
11Na 2 8 1 1 1
19K 2 8 8 1

16. 3. The Atomic Relative Mass of Element
The atomic relative mass of element is perbandingan massa rata-rata 1 atom suatu unsur dengan 1/12 massa 1 atom C-12.
Relative atomic mass=
One atomic mass
1/12 x one atomic mass of C-12
Example :
Mass 1 atom O
Ar O =
Assuming mass of 1 atom oxygen is 2,6505x gram, and mass avarage 1 C-12 is 2 x 10-24gram, how much is the atomic relative mass of oxygen ?
1/12 mass 1 atom C-12
2,6505 x 10-24gram
Ar O =
= 16
1/12 x 2 x 10-24gram