Parklands College Grade 10 Physical Science Chemistry Notes 2016
2.2.2 A Deeper Understanding of Atomic Structure
So this is what we have learnt thus far:
There are 3 types of subatomic particles in the atom:



Proton: carries a positive charge
Neutron: has roughly the same mass as the proton but carries no charge, hence it is neutral
Electron: which is 1/1836 the mass of a proton or neutron and carries a negative electric
charge
Particle
Proton
Neutron
Electron
Symbol
p+
n0
e-
Relative mass
1
1
1/1836
Charge
1+
0
1-
In this newer model of the atom:



The atom has a small centre or nucleus, which consists of protons and neutrons. The
nucleus has a positive charge because of the protons.
Surrounding the nucleus is a ‘cloud’ of electrons. The electrons move at nearly the speed
of light.
Most of the atom is empty space.
DID YOU KNOW?
If you had to expand an atom to the size of a modern day
football stadium, the equivalent size of the nucleus would be
that of a pea on the centre spot!!!!!
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Parklands College Grade 10 Physical Science Chemistry Notes 2016
1.
Atoms are not all identical. Each element is made up of a specific type of atom which has
a unique number of protons and electrons in it.
THE PERIODIC TABLE = a way of arranging the elements according to their
increasing proton numbers.
Proton number
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Parklands College Grade 10 Physical Science Chemistry Notes 2016
Nucleon number
Atomic number
EXAMPLE:
State the number of protons, neutrons and electrons in
19
F9:
PRACTISE:
1.
Textbook Pages 45 and 46 Questions 1, 2 and 4
2.
Ions = charged atoms
DEFINITION: An ion is an atom which has gained or lost electrons and as a result is
electrically charged.
Ions form when electrons are transferred from one atom to another.
The formation of a positive ion (cation) = the loss of electrons
The formation of a negative ion (anion) = gain of electrons
PRACTISE:
1.
Textbook Page 46 Questions 3 and 5
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