Phosphorus and Bromine Ion Properties

The video tutorial explains how to write the Lewis structure for PBr2-. It begins by counting the valence electrons: phosphorus has 5, each bromine has 7, and the negative charge adds one more, totaling 20 valence electrons. Phosphorus is placed in the center with bromines on either side. Electrons are paired between atoms to form bonds, and octets are completed for each atom. The formal charges are checked, showing phosphorus with a -1 charge and bromines with zero, aligning with the overall negative charge of the ion.

How many valence electrons does phosphorus contribute in the PBr2- ion?

• 9

• 5

• 3

• 7

What is the total number of valence electrons in the PBr2- ion?

• 19

• 20

• 18

• 21

Where is phosphorus placed in the Lewis structure of PBr2-?

• Above the bromines

• In the center

• On the left

• On the right

How many valence electrons are used to form bonds between phosphorus and bromine atoms?

• 6

• 4

• 2

• 8

What is the formal charge on each bromine atom in the PBr2- ion?

• -1

• 0

• +1

• +2

What is the formal charge on the phosphorus atom in the PBr2- ion?

• -2

• -1

• 0

• +1

Why does the PBr2- ion have a negative charge?

• Due to a positive charge on bromine

• Because of a missing electron

• Due to an extra valence electron

• Because of an extra proton