puts elements with similar properties
together, laid out in increasing proton
Arranging the elements like this
means that there are repeating
patterns in the properties of
If you know the properties of one
element in the group, you can predict
the properties of other elements.
Making predictions about reactivity
can be done because the elements
are arranged in this way.
Relative atomic mass= sum
of protons and neutrons
Ions and Formulas
Some metals, like iron, copper and tin form ions with different
charges. The number of brackets after the name tells you the
positive charge e.g. iron (II) has a charge of +2, so the ionic
formula is Fe2+.
The charges on an ionic compound add up to 0.
To balance ionic formulas one must put numbers in front of the numbers, like a
Ions are made when atoms gain or loose electrons.
Group 1 become positive ions when
they complete their outer shell.
Group 7 become negative ions when they
complete their outer shell.
Oppositly charged ions are strongly attracted to
each other. They stick to another oppositely
charged ion and form an ionic bond.
Sodium and Chlorine
Chlorine (7) picks up sodium's spare electron and
becomes a negative ion, as sodium (1) looses this electron
it becomes positive. As the two ions are now strongly
attracted to each other, they stick and form an ionic bond.
Solid ionic compounds (like sodium chloride)
are made up of giant lattice of ions. Each lattice
forms a single crystal.
The fact that the molten compounds of metals
and non-metals can conduct electricity is proof
that they're made up of ions.
Provides oxygen which
allows other materials
to burn more fiercely.
Can cause death either by
swallowing, breathing in, or
absorption through the skin.