3. Chemical Bonding

Question 1

Define electronegativity.

Answer 1

Electronegativity is the power of an atom to attract electrons to itself.

This is particularly in a covalent bond, and is with a pair of electrons.
An atom bonded to another of lesser electronegativity attracts both electrons, the whole bonding pair, to itself. This makes it more electronegative while the other is more electronegative.

Question 2

What are the 3 factors influencing the electronegativity of elements?

Answer 2

The 3 factors influencing the electronegativity of elements are:
1. Nuclear charge
2. Atomic Radius
3. Shielding by inner shells and subshells

Question 3

Explain the influence of nuclear charge on the electronegativity of an element.

Answer 3

Nuclear charge affects the attraction for electrons in the outer shell, and hence increased nuclear charge results in increased electronegativity.

As a result, electronegativity increases across a period.→

Question 4

Explain the influence of atomic radius on the electronegativity of an element.

Answer 4

The effect of atomic radius of an element on its electronegativity is: a smaller atomic radius means more electronegativity. The smaller an atom is, the more strongly its outer shell electrons are attracted to the nucleus.

As a result, electronegativity increases across a period, as atoms get smaller and decreases down a group as atoms gain shells and get larger.

Question 5

Explain the influence of shielding on the electronegativity of an element.

Answer 5

Shielding affects the electronegativity of an atom in that filled quantum shells can lessen the effect of nuclear charge on outer shell electrons, lessening attraction to the nucleus. Hence, increase in inner shells and subshells decreases electronegativity, as attraction decreases.