Covalent & Co-ordinate Bonding

Question 1

What is a covalent bond?

Answer 1

A shared pair of electrons between atoms

Question 2

What is a co-ordinate bond?

Answer 2

When one atom provides both the electrons needed to form a covalent bond

Question 3

What are the rules for Co-ordinate bonding?

Answer 3

• the atom donating the electrons must have a lone pair of electrons
• the atom receiving the electrons must have a vacant orbital
• bond represented with arrow instead of line

Question 4

Does a hydrogen ion have lone pairs or vacant orbital?

Answer 4

Vacant orbital

Question 5

Does water have lone pairs or vacant orbital?

Answer 5

2 Lone pairs (oxygen central atom - 2 electrons bonded to hydrogens, 4 left over)

Question 6

What is a lone pair?

Answer 6

Two electrons not used for bonding

Question 7

What is a vacant orbital?

Answer 7

Space for 2 electrons in their outer shell

Question 8

How is a double bond formed?

Answer 8

Atoms share two pairs of electrons to reach the octet e.g O=O

Question 9

Can the central atom be stable with fewer than 8 electrons?

Answer 9

Yes e.g BF3

Question 10

Can the central atom fit more than 8 electrons in its outer shell?

Answer 10

Yes if it’s in period 3 or higher it can expand the octet e.g PCl5

Question 11

What kind of bond is BrF3?

Answer 11

Covalent because both ions are in group 7 - 3 bonding pairs and 2 lone pairs

Question 12

What kind of bond is AlCl4- ?

Answer 12

Co-ordinate because the chloride ion (Cl-) donates both its electrons to the vacant orbital of the aluminium chloride (AlCl3)