Elements react to form
compounds by gaining or
losing electrons, or by sharing
electrons
Atoms of metals in group 1
combine with atoms of
non-metals in group 7 by
transferring electrons to form
ions that have the electronic
structures of noble gases
Ionic Bonding
Ionic compounds are
held together by strong
forces between the
oppositely charged
ions.
the ions from a giant
structure or lattice.
the strong forces of
attraction act
throughout the lattice
Formulae of ionic compounds
the charges on the
ions in ionic
compounds always
cancel each other out
the formula of an ionic
compound shows the
ratio of ions present in
the compound
sometimes we need
brackets to show the
ratio of ions in a
compound.
covalent bonding
a covalent
bond is formed
when two
atoms share a
pair of
electrons
the number of covalent
bonds depends on the
number of electrons it
needs to achieve a
stable electronic
structure.
Metals
the atoms in metals
are closely packed
and arranged in
regular layers
the electrons in the highest
energy level are delocalised.
the strong electrostatic
forces between these
electrons and the positively
charged metal ions hold the
metal together
Structure and Properties
Giant ionic structures
Ionic compounds have high
melting points and they are
all solids at room temperature
Ionic compounds will
conduct electricity when
we melt them or dissolve
them in water. their ions can
then move freely and can
carry charge through the
liquid