Question

select the correct answer. which structure is the lewis structure for ammonia (nh₃)? a.
vdots n - h - h - h
b.
h - n - h
|
h
c.
h - n - h
|
h
vdots
d.
h - n - h - h

Explanation:

To determine the correct Lewis structure for ammonia ($\ce{NH_3}$), we analyze the valence electrons:

• Nitrogen (N) has 5 valence electrons.
• Each Hydrogen (H) has 1 valence electron, and there are 3 H atoms, so $3\times1 = 3$ valence electrons from H.
• Total valence electrons: $5 + 3 = 8$.

In a Lewis structure, we want to satisfy the octet rule for N (8 electrons) and duet rule for H (2 electrons each).

• Nitrogen forms single bonds with 3 H atoms, using $3\times2 = 6$ electrons (3 bonds).
• The remaining electrons on N: $8 - 6 = 2$, which form a lone pair (2 electrons).

Now let's analyze the options:

• Option A: The N has a double bond? No, $\ce{NH_3}$ has single bonds. Also, the lone pair placement is incorrect.
• Option B: No lone pair on N? Incorrect, N should have a lone pair.
• Option C: N is bonded to 3 H atoms (single bonds) and has a lone pair (2 electrons). This satisfies the valence electron count and octet/duet rules.
• Option D: Incorrect bonding (extra bond or incorrect lone pair).

Answer:

C. $\ce{H - \overset{..}{N} - H}$ (with a third H bonded to N, as shown in the option's structure with N having a lone pair and three single bonds to H)