2.3 Chemical Bonds

Question 1

What happens with electrons during ionic bonds?

Answer 1

The atom with the higher EN “steals” valence electrons from the atom with the lower EN.

Question 2

What happens with electrons during polar covalent bonds?

Answer 2

The valence electron pairs are shared unequally between the two atoms.

Question 3

What happens with electrons during nonpolar covalent bonds?

Answer 3

The valence electron pairs are shared equally between the two atoms.

Question 4

Polar vs nonpolar

Answer 4

Polar covalent bonds are formed between atoms with slightly different EN. The electron pair is shared unequally, causing the compound to have two poles: partially positive and partially negative. The atom with the higher EN has a partially negative charge and the atom with the lower EN has a partially positive charge. Nonpolar covalent bonds are formed between atoms of equal EN. The electron pair is shared equally between the two atoms. The compound does not have two poles or different charges.

Question 5

Given two atoms, what type of bond will form between them and why?
Chlorine and chlorine

Answer 5

Nonpolar covalent
- No difference in EN
- Equal pull
- Get full valence shell through equal sharing of electron pair

Question 6

Given two atoms, what type of bond will form between them and why?
Chlorine and Potassium

Answer 6

Ionic
- large difference in EN (chlorine has a much higher EN than potassium)
- Chlorine has a stronger pull
- Get full valence shell through transferring electrons

Question 7

Given two atoms, what type of bond will form between them and why?
Chlorine and Carbon

Answer 7

Polar Covalent
- small difference in EN (chlorine is slightly higher)
- Chlorine has a stronger pull
- Get full valence shell through unequal sharing of electron pair

Question 8

How does EN determine what type of bond will form?

Answer 8

If two atoms have equal EN, they will form a nonpolar covalent bond. If there is a small difference in EN, the atoms will form a polar covalent bond. If there is a large difference in EN, the atoms will form an ionic bond.

Question 9

Ionic substances dissolve in water vs covalent substances dissolve in water

Answer 9

Ionic: bonds are broken in water (ions pulled apart)
Covalent: bonds are not broken in water (molecules pulled apart, not atoms)

Question 10

Which type of bond is more easily disrupted by water?

Answer 10

Ionic bonds are more easily disrupted by water than covalent bonds.