Which property of the third-row nonmetallic elements might be the one depicted below:

a. first ionization energy,

b. atomic radius,

c. electronegativity,

d. melting point,

e. X―X single-bond enthalpy? [Find more in Sections 22.3, 22.4, 22.6, 22.8, and 22.10]

Explain each of the following observations:

c. The boiling point of HF is much higher than those of the other hydrogen halides.

Write balanced equations for each of the following reactions.

e. Potassium peroxide reacts with CO₂(g) to give potassium carbonate and O₂.

Write a balanced equation for each of the following reactions:

a. Diborane reacts with water to form boric acid and molecular hydrogen.

Write a balanced equation for each of the following reactions:

b. Upon heating, boric acid undergoes a condensation reaction to form tetraboric acid.

Write a balanced equation for each of the following reactions:

c. Boron oxide dissolves in water to give a solution of boric acid.