Question:easy

What is the number of bond pair of electrons and lone pair of electrons present in the valence shell of chalcogens in their hydride ?

Show Hint

Chalcogens have 6 valence electrons and form H2X, so two electrons are shared and two pairs stay unshared.
Updated On: Oct 1, 2026
  • 2 - Bond pair and 1- lone pair of electrons
  • 2 - Bond pair and 2- lone pair of electrons
  • 3 - Bond pair and 1- lone pair of electrons
  • 3 - Bond pair and 2- lone pair of electrons
Show Solution

The Correct Option is B

Solution and Explanation

Step 1: Write the Lewis picture
Take $\text{H}_2\text{O}$ as the model. Oxygen has the configuration $2s^2 2p^4$, so 6 valence electrons.

Step 2: Distribute electrons
Two of the unpaired electrons of oxygen pair up with the electrons of the two hydrogens. The other four electrons stay on oxygen as two filled pairs.

Step 3: Result
Bond pairs = number of H atoms = 2. Lone pairs = $(6 - 2)/2 = 2$. The same count holds for the S, Se and Te hydrides.

Step 4: Rule out the rest
"3 bond pairs" belongs to group 15 hydrides such as $\text{NH}_3$, which has 1 lone pair. The option with 2 bond pairs and 1 lone pair would account for only 4 valence electrons on X (2 shared plus 2 unshared), which does not fit group 16.

Final Answer:
Group 16 hydrides carry 2 bond pairs and 2 lone pairs. This is option (B). \[ \boxed{\text{(B) }2 \text{ bond pairs and } 2 \text{ lone pairs}} \]
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