Question

Chlorine and bromine are in the same group in the periodic table. The bond energy of a Cl–Cl bond is 240 kJ/mol. The bond energy of a Br–Br bond is 190 kJ/mol. Which statement best explains this difference?(1 point)
Responses

Chlorine atoms form a double bond, and bromine atoms form a single bond.
Chlorine atoms form a double bond, and bromine atoms form a single bond.

Chlorine atoms are larger than bromine atoms.
Chlorine atoms are larger than bromine atoms.

Bromine atoms are more likely than chlorine atoms to interact with other atoms.
Bromine atoms are more likely than chlorine atoms to interact with other atoms.

Bromine has more electron levels than chlorine.

Answer 1

"Bromine has more electron levels than chlorine."

Reason: Bromine atoms have more electron shells (are larger), so their valence orbitals overlap less effectively than chlorine's. Less overlap gives a longer, weaker Br–Br bond and therefore lower bond energy.