Valence Shell Eelctron Pair Repulsion

Question 1

Why do we use a wedge in drawing 3D molecules

Answer 1

We use a wedge to show the bond is pointing towards us and a dashed line to show the bond pointing away from us. A normal line shows the bonds in the same plane as the page.

Question 2

What does the shape of the covalent mo,echoed depend on

Answer 2

Depends upon the number and type of e,extrinsic pairs that surround the central atom.

Question 3

What are the rules to find out the number of electron pairs

Answer 3

1. Look at the chemical formulae and find the central atom
2. Use your periodic table to work out the number of outer shell electrons. This is the same as the group number.
3. Add to this number the number of atoms that are bonded to the central atom.
4. Is it an ion. For positive ions take the charge away, for negative ions add the charge.
5. Divide the answer by 2 to find the number of pairs of electrons
6. Work out the number of bi ding pairs and line pairs.