Topic 2.1.3 - Covalent bonding

Question 1

What bond is formed when 2 s orbitals overlap?

Answer 1

sigma bond

Question 2

What bond is formed when 2 p orbitals overlap end over end?

Answer 2

sigma bond

Question 3

What bond is formed when 2 p orbitals overlap side by side?

Answer 3

pi bond

Question 4

What bond will H2 have?

Answer 4

sigma bond

Question 5

What happens of a diatomic molecule has 2 or more shared pair of electrons?

Answer 5

One sigma then pi bonds

Question 6

What bond is always formed first if there are 2 or more pairs of electrons being shared?

Answer 6

sigma, so pi bonds only exist between atoms joined by double or triple bonds

Question 7

Why do carbon’s covalent bonds have a higher boiling point than silicon’s?

Answer 7

Silicon atoms have a greater atomic radii meaning forces of attraction are weaker.

Question 8

The bond between fluorine atoms is shorter than between chlorines but the bond strength between chlorine atoms is larger, why?

Answer 8

Lone pairs of electrons on fluorine are very close to each other, therefore they repel each other strongly reducing bond strength.

Question 9

Why is the sigma bond between 2 carbon atoms in ethene stronger than the pi bond?

Answer 9

Area of highest electron density of a sigma bond is largely located between the 2 nuclei so forces of attraction are strong. And the overlap of the p orbitals end over end are more effective.
In the pi bond the areas of the highest electron density are further away from the nucleus so forces of attraction are lower