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Jump to one of the following Lewis structures' parts:   Choose One Introduction to Lewis Structures Part 1- Basics Part 2- Multiple Bonding and Polyatomic Ions Part 3- Resonance Part 4- Hypervalency Part 5- Formal Charge I Part 6- Formal Charge II Part 7- Electron Deficiency Part 8- Oxoacids Part 9- Quizzes

Pull up the Periodic Table if you need one.

Here's a current list of the rules.

Let's take a look at BeCl₂ and jump in with both feet.

Let's take a look at the final structure. Go ahead and calculate the formal charge for all of the atoms.

Your turn- enter your answer for the formal charges and hit "Verify"
Using this Lewis structure:
Formal charge for each chlorine.
Formal charge for beryllium.
Sum up the formal charges.

We can do better. The title of this section is a big clue- "electron deficient". Here's the Lewis symbol for beryllium-

Beryllium tends to only make 2 bonds instead of the typical 4 we're used to. So, we skip the last step when we satisfied the octet rule for the central atom. Calculate the formal charges for this structure-

Your turn- enter your answer for the formal charges and hit "Verify"
Using this Lewis structure:
Formal charge for each chlorine.
Formal charge for beryllium.
Sum up the formal charges.

To summarize, for beryllium compounds we stop at 2 bonds and we don't complete the octet for the central atom. Boron compounds work similarly. Here's the Lewis symbol for boron-

Boron compounds tend to have only three bonds to the central boron atom. Let's modify the list of the rules.

Now try BCl₃.

BCl3
Your turn- enter your answer for the formal charges and hit "Verify"
1.	Total number of valence electrons.
2. Draw the skeleton structure. 3. Connect the atoms by making bonds. 4. Satisfy the octet rule for the surrounding atoms. 5. Satisfy the octet rule for the central atom. (No need since it's an electron deficient compound)

Just to make sure, let's take a look at the formal charge for all the atoms.

Your turn- enter your answer for the formal charges and hit "Verify"
Using this Lewis structure:
Formal charge for each chlorine.
Formal charge for boron.
Sum up the formal charges.