H2S Lewis structure

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H2S Lewis Structure
H2S Lewis structure | Image: Learnool

H2S (hydrogen sulfide) has two hydrogen atoms and one sulfur atom.

In the H2S Lewis structure, there are two single bonds around the sulfur atom, with two hydrogen atoms attached to it, and on the sulfur atom, there are two lone pairs.

Steps

To properly draw the H2S Lewis structure, follow these steps:

#1 Draw a rough sketch of the structure
#2 Next, indicate lone pairs on the atoms
#3 Indicate formal charges on the atoms, if necessary

Let’s break down each step in more detail.

#1 Draw a rough sketch of the structure

  • First, determine the total number of valence electrons
Periodic table | Image: Learnool

In the periodic table, hydrogen lies in group 1, and sulfur lies in group 16.

Hence, hydrogen has one valence electron and sulfur has six valence electrons.

Since H2S has two hydrogen atoms and one sulfur atom, so…

Valence electrons of two hydrogen atoms = 1 × 2 = 2
Valence electrons of one sulfur atom = 6 × 1 = 6

And the total valence electrons = 2 + 6 = 8

  • Second, find the total electron pairs

We have a total of 8 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 = 8 ÷ 2 = 4

  • 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.

Hence, here we have to assume that the central atom is sulfur.

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

  • And finally, draw the rough sketch
H2S Lewis Structure (Step 1)
Rough sketch of H2S Lewis structure | Image: Learnool

#2 Next, indicate lone pairs on the atoms

Here, we have a total of 4 electron pairs. And two S — H bonds are already marked. So we have to only mark the remaining two electron pairs as lone pairs on the sketch.

Also remember that sulfur is a period 3 element, so it can 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. But no need to mark on hydrogen, because each hydrogen has already two electrons.

So for sulfur, there are two lone pairs.

Mark the lone pairs on the sketch as follows:

H2S Lewis Structure (Step 2)
Lone pairs marked, and got the stable Lewis structure of H2S | Image: Learnool

#3 Indicate formal charges on the atoms, if necessary

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

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

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

For sulfur atom, formal charge = 6 – 4 – ½ (4) = 0

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

In the above structure, you can see that the central atom (sulfur) forms an octet. And the outside atoms (hydrogens) also form a duet. Hence, the octet rule and duet rule are satisfied.

Therefore, this structure is the stable Lewis structure of H2S.

Next: OF2 Lewis structure

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Deep

Learnool.com was founded by Deep Rana, who is a mechanical engineer by profession and a blogger by passion. He has a good conceptual knowledge on different educational topics and he provides the same on this website. He loves to learn something new everyday and believes that the best utilization of free time is developing a new skill.

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