Structures and Bonding

• The strong electrostatic attraction between the ions holds the ions together ( Ionic Bond)
• Ions are packed together in a regular arrangement, called a crystal lattice
• The lattice is a giant structure with strong ionic bonds throughout the structure
• Happens between one metal and one non- metal atom

• Every ionic compound contains both positive and negative ions
• The total positive charge must be equal to the total negative charge so the overall compound is uncharged

• Eg. Magnesium Bromide
• Mg  , Br
• Therefore, a magnesium ion needs two bromide ions to make the compound neutral
• The formula is MgBr

• Eg. Calcium Hydroxide
• Ca  , OH
• Therefore, a calcium ion needs two hydroxide ions to make the compound neutral
• The formula is Ca (OH)
• This is because hydroxide contains two different elements, so they have to be put into brackets

The Crossover Rule: Write out the ions with their charges. Take the number on each charge and swap it with the opposite one:

• Formed between two non- metals
• The atoms share electrons to get a full outer shell

• Bonds between metals
• Electrons are free to move between atoms
• Strong bonds so the metals can maintain their structure and have a high boiling/ melting point