BeCl2 Lewis Structure

BeCl2 Lewis Structure

BeCl2 (beryllium chloride) has one beryllium atom and two chlorine atoms. In the lewis structure of BeCl2, there are two single bonds around the beryllium atom, with two chlorine atoms attached to it, and on each chlorine atom, there are three lone pairs.

Steps

Here’s how you can draw the BeCl2 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, beryllium lies in group 2, and chlorine lies in group 17.

Hence, beryllium has two valence electrons and chlorine has seven valence electrons.

Since BeCl2 has one beryllium atom and two chlorine atoms, so…

Valence electrons of one beryllium atom = 2 × 1 = 2
Valence electrons of two chlorine atoms = 7 × 2 = 14

And the total valence electrons = 2 + 14 = 16

  • Second, find the total electron pairs

We have a total of 16 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 = 16 ÷ 2 = 8

  • Third, determine the central atom

We have to place the least electronegative atom at the center.

Since beryllium is less electronegative than chlorine, assume that the central atom is beryllium.

Therefore, place beryllium in the center and chlorines on either side.

  • And finally, draw the rough sketch
BeCl2 Lewis Structure (Step 1)

#2 Mark Lone Pairs

Here, we have a total of 8 electron pairs. And two Be — Cl bonds are already marked. So we have to only mark the remaining six electron pairs as lone pairs on the sketch.

Also remember that beryllium is a period 2 element, so it can not keep more than 8 electrons in its last shell. And chlorine is a period 3 element, so it can keep more than 8 electrons in its last shell.

Always start to mark the lone pairs from outside atoms. Here, the outside atoms are chlorines.

So for each chlorine, there are three lone pairs, and for beryllium, there is zero lone pair because all six electron pairs are over.

Mark the lone pairs on the sketch as follows:

BeCl2 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 beryllium atom, formal charge = 2 – 0 – ½ (4) = 0

For each chlorine atom, formal charge = 7 – 6 – ½ (2) = 0

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

In the above structure, you can see that the central atom (beryllium) doesn’t form an octet. But, beryllium has an exception that it does not require eight electrons to form an octet. So no need to worry about the octet rule here.

Therefore, this structure is the stable lewis structure of BeCl2.

Next: N2F2 Lewis Structure

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