Lewis structure of H2Se

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The Lewis structure of H₂Se contains two single bonds, with selenium in the center, and two hydrogens on either side. There are two lone pairs on the selenium atom, and the hydrogen atom does not have any lone pair.

Steps

By using the following steps, you can easily draw the Lewis structure of H₂Se.

#1 Draw skeleton
#2 Show chemical bond
#3 Mark lone pairs
#4 Calculate formal charge and check stability (if octet is already completed on central atom)

Let’s one by one discuss each step in detail.

#1 Draw skeleton

In this step, first calculate the total number of valence electrons. And then, decide the central atom.

• Let’s calculate the total number of valence electrons

We know that… hydrogen is a group 1 element and selenium is a group 16 element. Hence, hydrogen has one valence electron and selenium has six valence electrons.

Now H₂Se has two hydrogen atoms and one selenium atom.

So the total number of valence electrons = (valence electrons of hydrogen atom × 2) + valence electrons of selenium atom

Therefore, the total number of valence electrons = 2 + 6 = 8

• Now decide the central atom

We can not assume hydrogen as 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, assume that selenium is the central atom.

So now, put selenium in the center and hydrogens on either side. And draw the rough skeleton structure for the Lewis structure of H₂Se something like this:

Also read: How to draw Lewis structure of COF₂ (5 steps)

#2 Show chemical bond

Place two electrons between the atoms to show a chemical bond. Since selenium is surrounded by two hydrogens, use four electrons to show two chemical bonds as follows:

Also read: How to draw Lewis structure of NO₂F (5 steps)

#3 Mark lone pairs

As calculated earlier, we have a total of 8 valence electrons. And in the above structure, we have already used four valence electrons. Hence, four valence electrons are remaining.

Two valence electrons represent one lone pair. So four valence electrons = two lone pairs.

Note that selenium is a period 4 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.

Also, make sure that you start marking these lone pairs on outside atoms first. And then, on the central atom.

The outside atoms are hydrogens. But hydrogen can not keep more than 2 electrons in its last shell. Hence, don’t mark the lone pairs on hydrogen.

So the central atom (selenium) will get two lone pairs.

Now draw the Lewis structure of H₂Se something like this:

In the above structure, you can see that the octet is completed on the central atom (selenium), and also on the outside atoms. Therefore, the octet rule is satisfied.

After completing the octet, one last thing we need to do is, calculate the formal charge and check the stability of the above structure.

Also read: How to draw Lewis structure of SiBr₄ (4 steps)

#4 Calculate formal charge and check stability

The following formula is used to calculate the formal charges on atoms:

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

Collect the data from the above structure and then, write it down below as follows:

• For each hydrogen atom

Valence electrons = 1
Nonbonding electrons = 0
Bonding electrons = 2

Formal charge = 1 – 0 – ½ (2) = 0

• For selenium atom

Valence electrons = 6
Nonbonding electrons = 4
Bonding electrons = 4

Formal charge = 6 – 4 – ½ (4) = 0

Mention the formal charges of atoms on the structure. So the Lewis structure of H₂Se looks something like this:

In the above structure, you can see that the formal charges of both (hydrogen and selenium) are zero. Therefore, this is the stable Lewis structure of H₂Se.

And each horizontal line drawn in the above structure represents a pair of bonding valence electrons.

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Related

• Lewis structure of COF₂
• Lewis structure of NO₂F
• Lewis structure of SiBr₄
• Lewis structure of CH₃NO₂
• Lewis structure of AsF₃

External links

• H2Se Lewis Structure, Geometry, Hybridization, and Polarity – Techiescientist
• H2Se Lewis Structure in 6 Steps (With Images) – Pediabay
• Chemical Bonding: H2Se Lewis Structure – The Geoexchange
• H2Se lewis structure, Molecular geometry, Polar or nonpolar, Bond angle – Topblogtenz
• How to draw H2Se Lewis Structure? – Science Education and Tutorials
• Draw the Lewis structure for H2Se. How many lone pairs of electrons are on selenium? – Homework.Study.com
• H2Se Lewis Dot Structure | Science, Chemistry – ShowMe
• Hydrogen Selenide, H2Se Molecular Geometry & Polarity – Tutor-Homework.com
• Draw Lewis structures for H2Se, and ClO3 – Chegg
• Determine the Lewis structure of H2Se – Quizlet
• What is the Lewis structure for H2Se – Brainly
• Draw the Lewis structure for H2Se. How many lone pairs of electrons are on selenium? – Course Hero