Valence Electrons in BH2- Structure

The video tutorial explains how to write the Lewis structure for BH2-. It begins by counting the valence electrons: boron has three, each hydrogen has one, and the negative charge adds an extra electron, totaling six. Boron is placed in the center with hydrogens on either side. Two electrons form bonds between boron and each hydrogen, and the remaining two electrons are placed on boron. The video highlights that boron and hydrogen are exceptions to the octet rule, requiring only six and two electrons, respectively, to be stable.

How many valence electrons does boron contribute in the BH2- ion?

• 3

• 4

• 1

• 2

What is the total number of valence electrons in BH2-?

• 4

• 6

• 5

• 7

Where is boron placed in the BH2- Lewis structure?

• On the left

• On the right

• Above hydrogen

• In the center

How many valence electrons are used to form bonds between boron and hydrogen in BH2-?

• 6

• 4

• 2

• 8

What is the exception to the octet rule for boron in BH2-?

• It needs 4 electrons

• It needs 8 electrons

• It needs 6 electrons

• It needs 2 electrons

How many valence electrons does hydrogen need to be stable in BH2-?

• 1

• 2

• 3

• 4

What is the final electron configuration for hydrogen in the BH2- structure?

• 3 electrons

• 2 electrons

• 1 electron

• 4 electrons