Ethane has a higher boiling point than methane because there are more bonds to break.

Carbon dioxide has a higher boiling point than methane because its atoms are held together by double bonds rather than single bonds.

Diamond has a high melting point because the atoms are all joined by covalent bonds in a lattice.

Diamond has a high melting point because there are strong covalent bonds between its molecules.

The metal is held together by the attraction between the copper ions.

Copper has a high melting point because there are strong forces of attraction between the copper ions and the free moving outer shell electrons.

The metal conducts electricity because the copper electrons are free to move.

Copper has a high melting point because there are lots of strong covalent bonds to break.

Copper can be bent because the layers of copper ions can slide relative to each other.

Each molecule of sodium chloride contains one sodium ion and one chloride ion.

Each sodium ion is attracted to one chloride ion.

The ions exist in pairs containing one sodium ion and one chloride ion.

Each sodium ion is bonded ionically to one chloride ion, and then to others by attractive forces.

There is a bond between the ions in each molecule, but no bonds between molecules.

An ionic bond is when one atom donates an electron to another atom.

A sodium ion can only form one ionic bond because it only has one electron in its outer shell.

The sodium ions and chloride ions are not joined to each other, but are attracted to each other by electrostatic attraction.

Each sodium ion is attracted to all the chloride ions surrounding it.

The ions are separated when in solution.

The sodium chloride molecules break apart when they dissolve.

The sodium and chloride ions move around in Na+ Cl– pairs.

The solution conducts electricity because electrons can pass through the solution.