[Unit 3.4] | Electronegativity: Bond Polarity In Covalent Bonds

Question 1

Define electronegativity.

Answer 1

• The tendency of a covalently bonded atom to draw the shared electron pair towards itself, in order to become “partially negative”.

• (Therefore the other becomes partially positive.)

Question 2

List 3 factors that impact electronegativity.

Answer 2

• Atomic Radius: The further the distance from the nucleus, the lower the attraction felt by the electrons.

• Nuclear Charge: More protons means more electrostatic attraction.

• Shielding: With more shells, there is less attraction.

Question 3

What trends in the electronegativity of atoms are found across a period?

Answer 3

• Lower atomic radius / nuclear charge
• Mininal increase in shielding

• Therefore there is a generally increasing trend.

Question 4

What trends in the electronegativity of atoms are found down groups?

Answer 4

• Increased atomic radius and shielding.

• Therefore a decreasing trend.

Question 5

What is the polarity of a covalent bond containing two of the same type of atom?

Answer 5

• Non-polar. Electron distribution is equal.

Question 6

What is the polarity of a covalent bond containing two different types of atom?

Answer 6

• Polar: the electron distribution is imbalanced.

• The more electronegative atom will be partially negative and the other partially positive.