Question

The ability of an atom in a molecule to pull bonding electrons toward itself is:

a)Paramagnetism

b)Diamagnetism

c)Effective nuclear charge

d)Electronegativity

e)Ionization potential

Given the electronegativity values below, select the single bond that is LEAST polar.

Element: H C N O

Electronegativity: 2.1 2.4 3.0 3.5

a) N-H

b) C-H

c) O-N

d) O-C

e) O-H

Answer 1

1. The ability of an atom to pull bonding electrons towards itself is called as electronegativity i.e. the correct answer is option d.

Paramagnetism is that form of magnetism where a material is weakly attracted by an externally applied magnetic field and tend to align itself in the direction of magnetic field.

Diamagnetism is that form of magnetism where a material is repelled by an externally applied magnetic field and tend to align itself in the direction opposite to that of magnetic field.

Effective nuclear charge is the net positive charge that an electron experiences in a multi-electronic system.

Ionization potential is the minimum amount of energy which is required to remove the most loosely bound electron from an isolated, gaseous atom to make it a uni-positive ion.

So the options a, b, c and e are incorrect.

2. The greater the difference in electronegativity between two atoms, the more polar will be the bond formed between them.

From the electronegativity values given here,

difference in electronegativity between N and H = 3.0 - 2.1 = 0.9

difference in electronegativity between C and H = 2.4 - 2.1 = 0.3

difference in electronegativity between O and N = 3.5 - 3.0 = 0.5

difference in electronegativity between O and C = 3.5 - 2.4 = 1.1

difference in electronegativity between O and H = 3.5 - 2.1 = 1.4

So the least difference in electronegativity exists between C and H atoms. Thus C-H bond will be least polar. Hence the correct answer is option b.