13 mark for review contains 1 sigma (σ) and 2 pi (π) bonds a b2 b n2 c o2 d f2

Explanation:

Step1: Recall bond - type in molecules

A triple - bond consists of 1 sigma ($\sigma$) and 2 pi ($\pi$) bonds.

Step2: Analyze each option

• $B_2$ has a double - bond (1 $\sigma$ and 1 $\pi$).
• $N_2$ has a triple - bond (1 $\sigma$ and 2 $\pi$).
• $O_2$ has a double - bond (1 $\sigma$ and 1 $\pi$).
• $F_2$ has a single - bond (1 $\sigma$).

Answer:

B. $N_2$