1.1.1 They consist of
three particles: the
proton, neutron and
220.127.116.11 electrons have a -1 charge.
18.104.22.168.1 electrons 'whizz' around
the nucleus of the atom
22.214.171.124.2 their relative mass is: 1/2000
126.96.36.199 protons have a +1
188.8.131.52.1 Relative mass: 1
don't have a
184.108.40.206.1 Relative mass: 1
2 Nuclear Symbols
2.1 you can work out the no. of protons,
neutrons and electrons from the
2.2 mass number: the
number of protons
and neutrons in the
2.3 atomic (proton)
protons in the
2.3.1 all atoms of the same
element have the same
3 Atoms and Ions
3.1 neutral atoms (no charge) have the same electron and proton
3.2 the neutron number is
just the mass no.
minus the atomic no.,
i.e. "the top minus the
bottom" (Nuclear Symbols)
3.3.1 Ions have different no. of protons and electrons.
3.3.2 Negative ions (e.g. Br-) have
more electrons than protons.
3.3.3 Positive ions (e.g. Mg2+) have more protons than electrons.
3.3.4 Exam Tip: Ions
220.127.116.11 Ions are easy to spot: they always have a plus or
minus charge (+ or -) next to them! If the charge is
a plus, it means an electron has been lost, e.g.
Mg2+ means that the Magnesium ion has lost two
electrons. If there is a minus sign, it means
electrons have been gained. For example, 3-
means 3 electrons have been lost!
4.1 isotope isn't just a scary science word,
nope! Isotopes of an element are atoms
with the same proton no., but different
4.1.1 basically atoms with the same
no. of protons but different
neutron no. are isotopes.
isotopes of the