Which pair of elements listed below would NOT form a covalent bond?

a
C and H
b
N and O
c
K and Cl
d
S and O

c

K and Cl

The pair of elements listed below that would NOT form a covalent bond is:

c. K and Cl

To determine which pair of elements would NOT form a covalent bond, we need to understand the nature of covalent bonds. In a covalent bond, two atoms share electrons in order to achieve a stable electron configuration.

Looking at the given options:

a. C and H (carbon and hydrogen): Carbon and hydrogen typically form covalent bonds. Both elements can easily share electrons to achieve a stable electron configuration.

b. N and O (nitrogen and oxygen): Nitrogen and oxygen can also form covalent bonds. Both elements have a tendency to gain or share electrons to complete their valence shells.

c. K and Cl (potassium and chlorine): Potassium and chlorine do NOT form a covalent bond. Instead, they form an ionic bond. Potassium readily donates an electron to chlorine, resulting in the formation of a positively charged potassium ion (K+) and a negatively charged chloride ion (Cl-).

d. S and O (sulfur and oxygen): Sulfur and oxygen can form covalent bonds. Both elements have a high electronegativity and can share electrons to achieve a more stable electron configuration.

Therefore, the pair of elements that would NOT form a covalent bond is option c: K and Cl (potassium and chlorine).