Know the names of the different models of the atom.
1st model – Solid sphere model (John Dalton)
2nd model – Plum pudding model (JJ Thomson)
3rd model – Nuclear model (Ernest Rutherford)
4th model (current day) - Bohr / Planetary model (Niels Bohr)
Know the relative mass and charge of each subatomic particle.
Subatomic particle Relative mass] Relative charge
Proton ] [ 1 ] [ +1 (positive)
Neutron 1 ] [ 0 ] [(neutral or no charge)
Electron Very small ] [ -1 ] [ (negative)
Know the order in which the different subatomic particles were discovered.
1st = Electrons, 2nd = Protons, 3rd = Neutrons (discovered by Chadwick)
Know where each subatomic particle is found in the atom.
Protons = in the nucleus
Neutrons = in the nucleus
Electrons = in shells around the nucleus
Know how to calculate the number of protons, neutrons and electrons in an atom.
Protons = 11
Neutrons = 23 – 11 = 12
Electrons = 11
[ 23]
[ Na]
[ 11]
Know what the atomic number and mass number tell us about an atom
The atomic number of an atom tells us the number of protons in the nucleus of the atom.
The mass number of an atom tells us the total number of protons and neutrons in the nucleus of an atom.
Know what isotopes are.
Isotopes are atoms that have the same number of protons but different numbers of neutrons.
Know how to calculate relative atomic mass (Ar).
Relative atomic mass (Ar) = [sum of (abundance x mass number) of all isotopes] ÷ 100
Know the maximum number of electrons that can fit on the 1st, 2nd, 3rd and 4th shells of an atom.
1st shell = 2,
2nd shell = 8
3rd shell = 8 and so on…
Know what all atoms want and explain why.
All atoms want a full outer shell, so they have a stable arrangement of electrons.
Describe how:
- a sodium (Na) ion would form.
- a fluoride (F) ion would form.
a) A sodium atom would lose one electron to form a sodium ion
b) A fluorine atom would gain one electron to form a fluoride ion.
Know what an ion is.
An ion is a charged particle (formed when an atom gains or loses electrons).
