Atomic Structure

An element is a pure substance which cannot be made into any simpler substance by chemical means.

Columns are called periods and rows groups.

Protons have a .............. charge.

Electrons have a ............. charge.

The atoms of an element contain a equal numbers of protons and electrons and so have no overall charge.

Every element has a unique atomic number. This is the number of electrons in the nucleus of each atom.

Mass number =

The number of neutrons can be calculated by subtracting

Metals form [blank_start]positive[blank_end] ions. Non-Metals form [blank_start]negative[blank_end] ions.

In a chloride ion the atomic number gives us 17 protons. The negative charge means we have one more electron than protons so we have 18 electrons. The mass number minus the atomic number gives us 18 neutrons.

The seven diatomic

The valency of sodium is 2.

The formula NaCl2 is correct for sodium chloride.

The formula Fe2(S04)2 is correct for iron(III)sulphate.

The formula for Sodium Sulphate is