Which is the correct Lewis dot structure of NH2-?

Question

Five Molecules Structures Option A as H single bond N single bond H, B as H single bond one electrons above and below N single bond H, C as two electrons above and below of N single bond H, D as H single bond two electrons above and below N
A.
A
B.
B
C.
C
D.
D
E.
E

Answer 1

To determine the correct Lewis dot structure of the amide ion (NH2^-), we first need to figure out the total number of valence electrons.

1. Counting Valence Electrons:

   • Nitrogen (N) has 5 valence electrons.
   • Each Hydrogen (H) has 1 valence electron, and there are 2 H atoms, contributing a total of 2 electrons.
   • The amide ion has an extra electron due to its negative charge.

   Total = 5 (N) + 2 (H) + 1 (extra for the negative charge) = 8 valence electrons.

2. Structure: The general structure of NH2^- involves nitrogen being the central atom bonded to two hydrogen atoms. We can visualize it as:

   • N is bonded to two H atoms.
   • N will have a lone pair of electrons to fulfill the octet rule, but since it can effectively accommodate only 5 electrons in total (by sharing the 2 electrons from the H atoms), it will have 1 lone pair remaining.
   • The negative charge on the ion indicates there is one extra electron, which is likely in the lone pair.

Now, let’s analyze the options given:

• In structures that show multiple pairs of electrons (like double bonds) or too many electrons around N compared to its capacity, those would be incorrect.
• The correct structure should have N with a lone pair of electrons and two single bonds with H.

Based on the descriptions:

• Option A indicates only single bonds to H, which is fine, but does not mention the lone pair on N.
• Option B mentions one electron above and below N, indicating a lone pair (this aligns more closely with NH2^-).
• Option C shows two electrons above and below which also indicates a stable lone pair.
• Option D mentions "two electrons above and below N" and then has H single-bonded to N, which does match a possible representation of NH2^-.

In summary, the best representation for NH2^- with two bonding pairs and a lone pair would be a structure that reflects that.

Thus, the correct answer is likely D, as it shows the two bonded H atoms connected to N and one lone pair on N to represent the negative charge. However, without a visual of the structures, confirming the most accurate description is still a bit challenging.