EL 3 - Bonding and Structure

Question 1

What is covalent bonding?

Answer 1

In a covalent bond, a pair of electrons is shared between two atoms. Covalent bonds are strong as there is a strong electrostatic attraction between these shared electrons and the nuclei of the bonded atoms

Question 2

Why do giant covalent lattices have a much greater melting point than simple covalent molecules?

Answer 2

The covalent bonds between the atoms in a giant covalent lattice are much stronger than the instantaneous dipole-induced dipole forces between the simple covalent molecules

Question 3

Why are ionic substances only conductive when dissolved?

Answer 3

When ions are in a solid, they are unable to move so they cannot carry charge. Dissolving the solid causes the ions to be more mobile, so they are free to carry charge

Question 4

Why do covalent and ionic lattices have high melting points?

Answer 4

Both lattices contain atoms that have multiple strong bonds around them, these bonds take a lot of (heat) energy to break

Question 5

What are the non-linear bond angle and conditions?

Answer 5

104.5 degrees
Two bonded pairs and two lone pairs

Question 6

What are the trigonal planar bond angle and conditions?

Answer 6

120 degrees
Three bonded pairs

Question 7

What are the trigonal pyramidal bond angle and conditions?

Answer 7

107 degrees
Three bonded pairs and one lone pair

Question 8

What are the tetrahedral bond angle and conditions?

Answer 8

109.5 degrees
Four bonded pairs

Question 9

What are the octahedral bond angle and conditions?

Answer 9

90 degrees
Six bonded pairs

Question 10

How do different numbers of bonded and lone pairs produce different shapes in molecules?

Answer 10

Lone pairs repel more than bonded pairs

Question 11

How does bonding occur in an ionic lattice?

Answer 11

The attraction between ions of different charges and the repulsion between ions of the same charge causes overall attraction in the lattice