U1-3-1 - Bond Polarity

Question 1

Formula for phosphorus

Answer 1

P₄

Question 2

Formula for sulfur

Answer 2

S₈

Question 3

Name all covalent network elements

Answer 3

Boron, silicon, carbon

Question 4

Pure covalent bond

Answer 4

A bond in which bonding electrons are shared equally.

Also called ‘non-polar bond’

Question 5

Polar bond

Answer 5

A bond in which bonding electrons are shared unequally and which has a permanent dipole.

Question 6

What causes chemical bonds to be polar?

Answer 6

Electronegativity difference between bonding atoms.

(usually ≥0.4)

Question 7

How do you determine the ‘ionic character’ of a bond?

Answer 7

Calculate electronegativity difference.

Higher ΔEN = more ionic character (bonding e^- shared less evenly)

Question 8

What do δ+ and δ− mean?

Answer 8

Delta plus/delta minus - partial charges

Question 9

A compound has a low melting/boiling point and does not conduct electricity in any form.

What bonding and structure does it have?

Answer 9

Covalent molecular

Question 10

A compound has a very high melting/boiling point and does not conduct electricity in any form.

What bonding and structure does it have?

Answer 10

Covalent network

Question 11

A compound has a very high melting/boiling point and conducts electricity when molten/dissolved.

What bonding and structure does it have?

Answer 11

Ionic (lattice)

Question 12

Li⁺₂S²⁻

What is wrong with this ionic formula?

Answer 12

More than one of Li⁺ present, must be shown in brackets:

(Li⁺)₂S²⁻