NH2+ is a polar molecule. Its Lewis structure consists of a central nitrogen atom (N), two hydrogen atoms (H) in the outer shell, and a positive charge in the outermost shell. The nitrogen atom (N) is connected to each of the two hydrogen atoms (H) by single bonds. The nitrogen atom (N) has one lone pair of electrons and a positive charge. However, to better represent the Lewis structure of this molecule, we generally place the charge outside the molecule, enclose the structural formula in square brackets, and mark the charge in the upper right corner (see the diagram below).

How to draw the Lewis structure of NH2+?

Step 1: Calculate the total number of valence electrons.

The total number of valence electrons in NH2+ is composed of the valence electrons of the nitrogen atom (N) plus the valence electrons of the two hydrogen atoms (H). According to the periodic table, the valence electrons of nitrogen (N) and hydrogen (H) are 5 and 1, respectively. However, because the molecule has a positive charge in the outermost shell... Therefore, the total number of valence electrons in an NH2+ molecule = 1 (5) + 2 (1) - 1 = 6.

Step Two: Determine the central atom.

In Lewis structure rules, the atom with lower electronegativity is the central atom, and the hydrogen atom is always in the outermost shell. Therefore, in the NH2+ molecule, the nitrogen atom (N) is the central atom.

Step 3: Label electron pairs and determine the molecular skeleton.

We place the nitrogen atom (N) in the middle and connect them by placing a pair of electrons between the atoms. That is, forming an H-N-H structure.

Step 4: Check if the atoms satisfy the octet rule.

In the above steps, we consumed a total of 4 valence electrons. Two valence electrons remain. And the outermost shell of a hydrogen atom can only hold 2 valence electrons to achieve a stable structure. Therefore, the remaining 2 valence electrons are placed on the nitrogen atom (N).

Step 5: Calculate the formal charge

Formal charge = Valence electrons – Nonbonding electrons – (Bonding electrons)/2

In the NH2+ molecule:

Formal charge of nitrogen atom (N) = 5 - 2 - 4/2 = +1;

Formal charge of hydrogen atom (H) = 1 - 0 - 2/2 = 0

Through the above calculation of formal charge, we can see that the charge of nitrogen atom (N) is +1, and the charge of hydrogen atom is 0. Finally, enclose the above structure in square brackets and mark a positive charge in the upper right corner to obtain the Lewis structure of the NH2+ molecule.