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CHAPTER 1
PERIODIC SYSTEM OF THE
ELEMENTS AND ATOMIC
STRUCTURE
Sistem Periodik Unsur dan
Struktur Atom
Teaching Learning Objectives
 The student
theory.
 The student
theory.
 The student
theory.
 The student
theory.
can explain of Dalton’s atomic
can explain of Thomson’s atomic
can explain of Rutherford’s atomic
can explain of Neils Bohr’s atomic
A. Model and Theory of Atom
1. 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.
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.
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
Atom model of Dalton
reaction of atom
 An atom of an element is permanent,
can’t de divided or created or
destroyed
2. Dalton’s Atomic Theory and
Model
Dalton suggested as followed :
a. Atom is the smallest particle of matter
b. Atom is small sizes and round-shaped,
indivisible, neither created nor destoyed.
c. All atoms of given element are identical
d. Atoms of different element can be joined to
produce substance with fixed scale.
e. Atoms combine to make compounds: a given
compound always has the same relative
number and kind of atoms
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.
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.
5. Bohr’s Model and Atomic Theory
Bohr’s atomic theory can be comprehended as
follow;
a. Electrons are moving around nucleus in
discreet level of energy.
b. 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.
PARTIKEL DASAR ATOM
Partikel Lam
Atom bang
Massa
Muatan
Penemu
gram
sma
Coulomb
Pem
bu
lat
an
Proton
1
1p
1,67 x 10-24
1,007276
+1,602x10-19
+1
Goldstein
Neutron
1
n
1,67 x 10-24
1,008665
0
0
Chadwick
Elektron
0
-1e
9,11 x 10-28
0,000548
-1,602x10-19
-1
Thomson
0
B. Application of Chemical Element
Periodic Table
1. Calculate the Amount of Proton,
Electron and Neutron of Atom
A
zX
X : atom or elements symbol
A : mass number= the total amount of proton and
neutron
Z : atomic number = the amount of proton
Example :
23
Atom Na is neutral atom
11 Na
Atomic number = z = 11 = proton number = electron number
Mass number = A= 23 = proton + neutron number
Neutron number = 23 – 11 = 12
+
+
23
Atom
Na
is positive ion
11 Na
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
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
2. Electron Configuration
Electron Configuration is construction of electron in atom shells
2
The maximum amount in every shell is 2n
Shell (n) Max Electron
Number (2n2)
1
2
2
8
3
18
4
32
Atomic Electron Configuration
Atomic
Element
Atomic Shell
K L M N O P Q
Valence
Electron
3Li
2 1
1
9F
2 7
7
11Na
2
8 1
1
19K
2
8 8 1
1
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 :
Ar O =
Assuming mass of 1 atom oxygen is
2,6505x 10-24 gram, and mass avarage
1 C-12 is 2 x 10-24gram, how much is
the atomic relative mass of oxygen ?
Mass 1 atom O
1/12 mass 1 atom C-12
2,6505 x 10-24gram
Ar O =
= 16
1/12 x 2 x 10-24gram