This is Neon. He is a stable atom. This makes him happy! All atoms want to have a full outer shell of electrons. This is 2 on the first shell and 8 on the rest of the shells. This is Neon. He is a stable atom. This makes him happy! Why is he stable?

What could you suggest to help them out? fluorine lithium beryllium These atoms are all unstable as they do not have full outer shells of electrons. What could you suggest to help them out? sodium chlorine oxygen hydrogen

8 electrons in outer shell Chlorine is stable Sodium has lost an electron. It now has a +1 charge Chlorine has gained an electron. It now has a -1 charge X X chlorine X sodium X X X X X X X X X ionic bond X X X X X Sodium is stable 8 electrons in outer shell Chlorine is stable 8 electrons in outer shell They are now bonded together to make a compound called sodium chloride. This giving and taking of electrons is called ionic bonding.

One electron donated One electron accepted NaCl sodium chloride METAL NON-METAL One electron donated One electron accepted NaCl sodium chloride

Ionic Bonding Normally happens between non-metals and metals. Ionic bonding is a transfer of electrons Metals always produce positive ions. Non-metals always produce negative ions.

8 electrons in outer shell Oxygen is stable 8 electrons in outer shell Calcium has lost two electrons. It now has a +2 charge Oxygen has gained two electrons. It now has a -2 charge X X oxygen calcium X X X ionic bond X X X Calcium is stable 8 electrons in outer shell Oxygen is stable 8 electrons in outer shell They are now bonded together to make a compound called calcium oxide. This giving and taking of electrons is called ionic bonding.

Working out the Formula of an Ionic Compound Positive Ions Negative ions All Group 1 All Group 2 2- ions 1- ions Li + Mg 2+ Carbonate CO32- Hydroxide OH- Na + Ca 2+ Sulphate SO42- Nitrate NO3- K + All Group 6 All Group 7 O2- F- S2- Cl- Br- I-

Working out the Formula of an Ionic Compound The charges of the ions in a compound have to balance. For example, What is the formula of sodium hydroxide? Sodium ion is Na+ Hydroxide ion is OH- You only need one of each ion to balance the charges so the formula of sodium hydroxide is NaOH.

Working out the Formula of an Ionic Compound The charges of the ions in a compound have to balance. For example, What is the formula of magnesium chloride? Magnesium ion is Mg 2+ Chloride ion is Cl- You need two Chloride ions to balance the charge of one Magnesium ion so the formula of magnesium chloride is MgCl2.

Work out the Formulae Try the exercises on the worksheet