N2H4 Lewis Structure

N2H4 Lewis Structure

N2H4 (hydrazine) has two nitrogen atoms and four hydrogen atoms. In the lewis structure of N2H4, there is a single bond between the two nitrogen atoms, and each nitrogen is attached with two hydrogen atoms, and on each nitrogen atom, there is one lone pair.

Steps

Here’s how you can draw the N2H4 lewis structure step by step.

Step #1: draw sketch
Step #2: mark lone pairs
Step #3: mark charges (if there are)

Let’s break down each step in detail.

#1 Draw Sketch

  • First, determine the total number of valence electrons

In the periodic table, nitrogen lies in group 15, and hydrogen lies in group 1.

Hence, nitrogen has five valence electrons and hydrogen has one valence electron.

Since N2H4 has two nitrogen atoms and four hydrogen atoms, so…

Valence electrons of two nitrogen atoms = 5 × 2 = 10
Valence electrons of four hydrogen atoms = 1 × 4 = 4

And the total valence electrons = 10 + 4 = 14

  • Second, find the total electron pairs

We have a total of 14 valence electrons. And when we divide this value by two, we get the value of total electron pairs.

Total electron pairs = total valence electrons ÷ 2

So the total electron pairs = 14 ÷ 2 = 7

  • Third, determine the central atom

Here hydrogen can not be the central atom. Because the central atom is bonded with at least two other atoms, and hydrogen has only one electron in its last shell, so it can not make more than one bond.

Now there are only two atoms remaining and both atoms are nitrogen, so we can assume any one as the central atom.

Let’s assume that the central atom is right nitrogen.

Therefore, place nitrogens in the center and hydrogens on either side.

  • And finally, draw the rough sketch
N2H4 Lewis Structure (Step 1)

#2 Mark Lone Pairs

Here, we have a total of 7 electron pairs. And five bonds are already marked. So we have to only mark the remaining two electron pairs as lone pairs on the sketch.

Also remember that nitrogen is a period 2 element, so it can not keep more than 8 electrons in its last shell. And hydrogen is a period 1 element, so it can not keep more than 2 electrons in its last shell.

Always start to mark the lone pairs from outside atoms. Here, the outside atoms are hydrogens and left nitrogen. But no need to mark on hydrogen, because each hydrogen has already two electrons.

So for each nitrogen, there is one lone pair.

Mark the lone pairs on the sketch as follows:

N2H4 Lewis Structure (Step 2)

#3 Mark Charges

Use the following formula to calculate the formal charges on atoms:

Formal charge = valence electrons – nonbonding electrons – ½ bonding electrons

For each nitrogen atom, formal charge = 5 – 2 – ½ (6) = 0

For each hydrogen atom, formal charge = 1 – 0 – ½ (2) = 0

Here, both nitrogen and hydrogen atoms do not have charges, so no need to mark the charges.

And in the above structure, you can see that the central atom (right nitrogen) forms an octet. Hence, the octet rule is satisfied.

Therefore, this structure is the stable lewis structure of N2H4.

Next: CH3NH2 Lewis Structure

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