[Unit 3.2] | Covalent Bonding

Question 1

What is a covalent bond?

Answer 1

A bond where 2 non-metal atoms share an electron pair to gain a full outer shell. It is formed by the attraction between the positive nuclei and the negative electrons.

Question 2

Define a lone pair of electrons.

Answer 2

Pairs of electrons that are uninvolved in covalent bonding. They are often found in Group 5-7 elements.

Question 3

What is the Octet Rule and what is the exception to it?

Answer 3

• The Octet rule suggests that the central atom of a covalently bonded molecule should aim to have a full outer shell (8 electrons).

• Beryllium and Boron do not have enough unpaired electrons to form octets.
• Period 3 non-metals can have more than 8 electrons in their outer shell.

Question 4

What is a dative covalent bond?

Answer 4

• It is a covalent bond where both electrons in the pair are provided by only one of the atoms.

• In diagrams, it is denoted with an arrow pointing away from the atom providing both electrons.