Question

The sum of covalent bonds in $H_2$, $N_2$ and $HCl$ is

• A. 4
• B. 5
• C. 6
• D. 3

Hint:

Always identify the group number of the element to determine how many electrons are needed for a stable octet. The number of electrons needed usually equals the number of covalent bonds the atom will form.

Answer 1

The Correct Option is B

To find the total sum of covalent bonds, we must analyze the bonding structure of each individual molecule based on the octet rule and valence electrons. 1. Hydrogen Molecule ($H_2$): Hydrogen has one valence electron. To achieve a stable duplet configuration, two hydrogen atoms share one pair of electrons. $$\text{Bonds in } H-H = 1$$

2. Nitrogen Molecule ($N_2$): Nitrogen belongs to Group 15 and has five valence electrons. To achieve an octet, each nitrogen atom requires three more electrons. Thus, they share three pairs of electrons, forming a triple bond. $$\text{Bonds in } N \equiv N = 3$$

3. Hydrogen Chloride ($HCl$): Hydrogen needs one electron to complete its duplet, and Chlorine (Group 17) needs one electron to complete its octet. They share one pair of electrons. $$\text{Bonds in } H-Cl = 1\lt strong\gt 4. Total Calculation:\lt /strong\gt \text{Sum} = (\text{Bonds in } H_2) + (\text{Bonds in } N_2) + (\text{Bonds in } HCl)$$ $$\text{Sum} = 1 + 3 + 1 = 5$$ Therefore, the total sum of covalent bonds in these three molecules is 5.