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SULPHATES.......:

Blue vitriol is copper(II) sulphate, CuSO₄.5H₂O

Green vitriol is iron(II) sulphate, FeSO₄.7H₂O

White vitriol is zinc sulphate ZnSO₄.7H₂O

Epsom salt is magnesium sulphate MgSO₄.7H₂O

Glauber salt is sodium sulphate, Na₂SO₄.10H₂O

Plaster of Paris is calcium sulphate 2CaSO₄.H₂O

Gypsum is calcium sulphate CaSO₄.2H₂O.

Carbonates..........:

Washing soda is hydrated sodium carbonate: Na₂CO₃.10H₂O
Baking soda is sodium bicarbonate: NaHCO₃

Numerous minerals are metallic carbonates. Some common ones are

Limestone: calcium carbonate, CaCO₃
Malachite: magnesium carbonate, CuCO₃.Cu(OH)₂
Magnesite: magnesium carbonate, MgCO₃
Dolomite: calcium magnesium carbonate, CaCO₃.MgCO₃

HALIDES........... :

NOW CHEMICAL BONDING...............!!!!!!!!!!!!!!!!!!!

Molecular shape:

Molecules are solid objects existing in 3-dimensional space. They have specific dimensions and shapes which are a consequence of the types of bonds from which they are made up. The simplest shapes are found in linear molecules, angular molecules, pyramidal molecules, and tetrahedral molecules.

The molecular formula of a substance does not give an indication of its shape. For example, CO₂ is a linear molecule, but SO₂ is angular.

Linear molecules

This is the simplest shape that any molecule can have. All the atoms in the molecule lie along a straight line. All diatomic molecules must be linear, but more complex molecules, such as CO₂ (illustrated below), are also linear. In the case of CO₂, the bond angle O-C-O is 180º.

Angular molecules:

A common situation encountered with molecules having three atoms, is the one where the two covalent bonds are at an angle. Water, H₂O, is a good example of this:

The H-O-H bond angle has a value of 104.5º.

Pyramidal molecules:

Ammonia, NH₃, is a good example of a pyramidal molecule. Imagine the nitrogen atom being at the apex of a regular pyramid, with the H-N bonds forming its sides.

There are three H-N-H bond angles, which all have the value of 107.3º.

Tetrahedral molecules

Methane, CH₄, is a tetrahedral molecule, in that the carbon atom lies at the centre of a regular tetrahedron, with each of the four hydrogen atoms being positioned at one apex:

There are four H-C-H bond angles, all of which have a value of 109.50º. Other examples of tetrahedral molecules are the ions NH₄⁺ and SO₄^2-.