Dative And Coord

Question 1

What is a lone pair electron ?

Answer 1

The electrons not involved in bonding (LPE) and you get them in elements in G5,G6 and G7.
Oxygen has 2 pairs of lone pair electrons.

Question 2

What is dative bonding

Answer 2

It’s a type of bonding formed with LPE they don’t look much different to covalent bonds
E.g.
NH3 + H+ -> NH4+
This is able to form as there are 2 lone ‘pair’ electrons on nitrogen which then bind to hydrogen

Question 3

What are some examples of dative bonds?

Answer 3

Hydronium, aluminium chloride dimer, ammonium ion, carbon monoxide
Hydronium has an overall positive charge so it repels other hydrogen ions

Question 4

Why does NH3 react readily with BF3 to form a stable compound?

Answer 4

N of NH3 has a lone pair on the N atom. The B atom of BF3 has an incomplete energy level and can form a dative bond with the N atom.

Question 5

Describe the bonding in the AlH4- ion

Answer 5

Al (G3) provides 3 electrons for bonding
Al can form 3 covalent bonds with H
Al has only 6 e- in its outer shell when bonded to 3H
Al can accept an e-pair from H+ to form a dative bond.

Question 6

What do lone pairs do?

Answer 6

They can affect the shape of the molecule