Atoms, IONS and
Molecules
(By Sumiati))
Objectives
1. The definition of atoms, molecules, and ions
2. The relationship of atoms, molecules, and
ions.
3. The Examples of substances consisting of
atoms, molecules, and ions.
4. The differences of element molecules and
compound molecules.
5. The examples of simple molecules in everyday
life.
Kelas 8B ulangan
 Jum”at depan, 18 nov .. Ulangan 3 bab.
 1. sistem pernapasan (bab4)
 2. sistem peredaran darah (bab 5)
 3. atom, ion dan molekul (bab 1 kimia)
 bilingual
What is a matter/substances?
Matter or substances is
everything having mass and
occupy a space.
Matter Classification
 Element = substance that cannot be broken down into
simpler substance by chemical methods. Ex: O2, O3,
H2, N2
 Compound = the combination of some elements
formed through a chemical reaction. H2O, CO2,
C6H12O6
 Mixtures = substances consisting of two or more
substances formed without a chemical reaction. Ex”
teh manis, juice,
Particle of Matter
Atoms
Ions
Molecules
 Ulangan bab 4,5 1 kimia
What is an Atom?
An atom is the smallest particle of
an element.
An atom has an average size of
about 0.0000000001 m or
–10
1 x 10 m.
ATOMS MODEL
(John Dalton)
ATOMS MODEL
(J.J Thomson)
ATOMS MODEL
ATOMS MODEL
(Niels Bohr)
ATOMS MODEL N=2-5 O=2-6
23.3 Representing an Atom of an Element
 Using chemical symbols
F
Li
B
He
H
C
N
O
Mg
Ne
Na
Cl
Cu
23.4 What is an Atom Made Up of?
 Each atom is made up of even smaller particles.
 These particles are called sub-atomic particles.
 Types of sub-atomic particles – protons, electrons
and neutrons
23.4 What is an Atom Made Up of?
 The table below summarises the properties of
protons, neutrons and electrons.
Sub-atomic
particles
Symbol
Relative charge
Proton
p
+1
Neutron
n
0
Electron
e
-1
23.5 Proton (Atomic) Number and Mass
Number
mass number
proton number
A
Z
X
chemical symbol
The atomic number or proton number is
the number of protons in an atom.
(=electron number)
The mass number is the total number of
protons and neutrons in an atom.
Kelompok kimia 8B
 Kelompok 1 ; dzikra,11,21,29,3,38,18, … ion…(75)
Kelompok 2 ; byan,aci.adit,maska,nabjas,tiara,dinda
…molekul… …(nilai 78)
 Kelompok 3 ; ageng.1,7,9,10,19,16,20 …atom (nilai 80)
 Kelompok 4 : muthia, mine, rania, clara, mirshaan,
sule molekul (bonus 5
 Kelompok 5 ; dika ….. Atom; Rizki, lia, afi, imae,
senopati…nilai 78+4
 Kelompok 6 : aldi …..ion:Reza,Rian,Ayu,Monika,Rara ..
Nilai 80+5
 Tugasnya: lirik lagu dikumpul sekarang …. Buat
 Tugasnya: lirik lagu dikumpul sekarang …. Buat
lagu… atom, ion, molekul. Yg ngumpul sekarang
sarusnya 10.
 Lirik lagu mengenai semua pembahasan tentang
atom, ion, molekul. Ketua kelompok ambil undian:
 Lagu in english…
 Hari selasa depan dinyanyikan ke depan berkelompok
 Menyanyi sambill bergaya
Periodic Table
35
Cl
23
11
1
1
Na
H
12
6
C
56
P
27
Ca
32
15
40
20
Fe
26
13
16
Al
S
23.6 What are Ions?
 When an atom loses or gains electrons, we say that an
ion is formed.
 An ion is an atom that carries a positive or negative
charge as a result of having lost or gained one or more
electrons.
 Atoms which lose electrons will have a net positive
charge. Hence, they form positive ions.
neutral
atom
atom with net positive charge
+
+ e–
electron lost by
atom
23.6 What are Ions?
 Atoms which gain electrons will have a negative
charge. Hence, they form negative ions.
neutral
atom
+ e–
electron gained by atom
atom with net
negative charge
-
23.6 What are Ions?
Example 1
Magnesium chloride is a compound made from two kinds of
ions – magnesium ions, which have a positive charge, and
chloride ions, which have a negative charge.
A magnesium atom has the chemical symbol, Mg.
A magnesium atom (an atom of a metal) loses two electrons to
form a magnesium ion in its compound.
Mg
Mg2+
Magnesium atom
Magnesium ion
+
2e –
Electrons
23.6 What are Ions?
Example 1
Magnesium atom
Magnesium ion
Number of protons
12
12
Number of electrons
12
10
Net charge
0
+2
A magnesium ion has 12 protons and 10 electrons.
Hence, it has a net positive charge of +2.
23.6 What are Ions?
Example 2
A chlorine atom has the chemical symbol, Cl.
35
A chlorine atom (an atom of a non-metal) gains
an electron
17
to form a chloride ion in its compound.
Cl
+
Chlorine atom
Cl-
eElectron
Chloride ion
Chlorine atom
Chloride ion
Number of protons
17
17
Number of electrons
17
18
Net charge
0
–
1
A chloride ion has 17 protons and 18 electrons. Hence, it has a
net negative charge of –1.
23.6 What are Ions?
 The table
below showsChemical
some ions
formed by common
Element
symbol
Ion formed
atoms:
Hydrogen
H
H+
Sodium
Na
Na+
Potassium
K
K+
Aluminium
Al
Al3+
Calcium
Ca
Ca2+
Magnesium
Mg
Mg2+
Oxygen
O
O2-
Chlorine
Cl
Cl-
Bromine
Br
Br-
Sulphur
S
S2-
23.7 What are molecules?
 A molecule is made up of two or more
atoms chemically combined together.
 Molecules of elements usually consist of a
fixed number of one type of atom
chemically combined together.
 Molecules of compounds contain a fixed
number of different types of atoms
chemically combined together.
Molecules of elements
Molecule
Hydrogen gas
H2
Molecular diagram
H H
Oxygen gas
O
O
N
N
Nitrogen gas
Molecular model
(ball and stick)
Molecules of compounds
Molecule
Water
Molecular diagram
H
O
H
Carbon dioxide
O C O
Ammonia
H
H
N
H
Hydrogen
chloride
H
Cl
Molecular model
(ball and stick)
GRATITUDE