1 - PRINCIPLES OF CHEMISTRY 

Ionic bonding - 

• Atoms lose or gain electrons to form charged particles (ions) 
• Strongly attracted to one another because of the opposite charges - electrostatic attrcation 
• High melting and boiling points 
• Dot and cross diagrams (with square brackets and charge) 

Losing electrons = oxidation 
Gaining electrons = reduction 

Shell less than half full of electrons - 

• Left hand side of periodic table 
• Want to become more stable like the noble gases 
• Try to lose the electron - easier than completing shell
• Become positive 
• Gives electron to oppositely charges atom wanting to complete shell - stick together 

Shell more than half full of electrons - 

• Right hand side of periodic table (group 6 and 7) 
• Gain extra electrons to complete shell 
• Become negative 

- Groups 1, 2 (metals) and 6, 7 (non-metals) are the most likely to form ions  

Giant ionic structures - 

• Compounds with ionic bonding always have giant ionic structures 
• Ions held together in closely packed 3D lattice (attraction between oppositely charged ions - very strpmg) 
• A lot of energy is needed to overcome the strong forces of attraction - high melting and boiling points 
• The more charged it is, the stronger the forces of attractions are