Question

Correct number of lone pairs in $SF_{4}$ and $H_{2}O$ molecules, respectively, should be ________.

• A. 1 and 2
• B. 2 and 1
• C. 1 and 1
• D. 2 and 2

Hint:

Lone Pairs = (Valence Electrons - Bonding Electrons) / 2.

Answer 1

The Correct Option is A

Step 1: Concept
Lone pairs are calculated using valence electrons and bonding electrons.
Step 2: Analysis of $SF_4$
Sulfur has 6 valence electrons. It forms 4 single bonds with Fluorine (using 4 electrons). Remaining electrons = $6 - 4 = 2$ (which forms 1 lone pair).
Step 3: Analysis of $H_2O$
Oxygen has 6 valence electrons. It forms 2 single bonds with Hydrogen (using 2 electrons). Remaining electrons = $6 - 2 = 4$ (which forms 2 lone pairs).
Step 4: Conclusion
Hence, the number of lone pairs is 1 and 2 respectively.
Final Answer:(A)