Reactivity and the Periodic Table

The reactions of an element depend upon the arrangement of electrons in the outer shell of its atoms.

Atoms ‘want’ a full outer shell and so metals lose an electron, and non-metals gain one to complete.

Noble gases (group 8) lack of reactivity because they already have a full outer shell of electrons.

As we move __________ the alkali metals (group __________) in the periodic table the reactivity increases. This is because the greater the number of shells, the __________ the outer shell is from the nucleus. Therefore the easier it is for an electron to be __________.

As we move __________ the halogens (group __________) in the periodic table the reactivity increases. This is because the fewer the number of shells, the __________ the outer shell is to the nucleus. Therefore the easier it is for an electron to be __________.

This is because the electrostatic force between the __________ nucleus and the __________ electron is stronger when there is little separation.