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Properties of Ionic Compounds

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• Ho Kin Keung (3)

• Lam Cho Yuen(4)

• Lam Po Wa(5)

• Lee Ho Yin (8)

• Ng Sai Cheong(11)

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Contents

• What are ionic compounds?

• What are the properties of ionic compounds?

• Formulae of ionic compounds

What are ionic compounds?

• In chemistry, an ionic compound is a chemical compound in which ions are held together in a lattice structure by ionic bonds.

• Usually, the positively charged portion consists

of metal cations and the negatively charged portion is a simple anion or polyatomic anion.

• The charge on each ion is determined by the number of electrons gained or lost so that the ion contains an octet of electrons in its outer shell.

What are the properties of ionic compounds?

• Formation of crystals : Ionic compounds form large crystals that we can see with the naked eye . Salt is one the examples.

• High melting and boiling points : Crystals are basically great big blocks of positive and negative charges all stuck together. To break the positive and negative charges apart, it takes a huge amount of energy.

What are the properties of ionic compounds?

• Hard and very brittle : Ionic compounds are so hard , so they don't bend at all.  This also explains the brittleness of ionic compounds. It takes a lot of energy to pull ionic charges apart from each other.

• Conducting electricity when dissolving in water : For example , when we take a salt and dissolve it in water, the water molecules pull the positive and negative ions apart from each other.

Formulae of ionic compounds• Composition of ionic compounds

The composition of ionic compounds is determined by the requirement that the compounds must be electrically neutral. That is that the charges of the cations and anions must balance or 'cancel" out one another. Below are examples of simple ionic compounds made up of single atom (monatomic) ions:

• Polyatomic ions and compounds

Most polyatomic ions are anions with one notable exception - the ammonium cation (NH4

+). The composition of salts with polyatomic ions is determined by the same rule as with monatomic ions. A few example are given below:

~The End~