Lewis Structures and Valence Electrons

The video tutorial explains how to draw Lewis structures for ions, including both anions and cations. It covers the rules for adding or subtracting electrons based on the charge of the ion. The tutorial provides detailed examples with nitrate and ammonium ions, showing how to count valence electrons and draw the structures. Additional examples with sulfate and phosphate ions are also discussed.

What is the main difference in handling electrons when drawing Lewis structures for anions and cations?

• Both anions and cations require subtracting electrons.

• Both anions and cations require adding electrons.

• Anions require subtracting electrons, while cations require adding electrons.

• Anions require adding electrons, while cations require subtracting electrons.

How many total valence electrons are there in the nitrate ion (NO3-)?

• 25

• 24

• 23

• 22

For the ammonium ion (NH4+), what is the total number of valence electrons after accounting for the charge?

• 7

• 10

• 9

• 8

What is a necessary step when completing the Lewis structure for the nitrate ion?

• Removing an electron from one oxygen.

• Forming a triple bond between nitrogen and oxygen.

• Forming a double bond between one oxygen and nitrogen.

• Adding an extra electron to nitrogen.

In the ammonium ion, how are the valence electrons distributed?

• Extra electrons are added to hydrogen atoms.

• Electrons are removed from nitrogen.

• Electrons are shared equally between nitrogen and hydrogen.

• All electrons are used up by placing hydrogens around nitrogen.

When drawing Lewis structures, what is the first step after determining the number of valence electrons?

• Distribute electrons around the central atom.

• Draw the molecule with the correct connectivity.

• Add extra electrons to the central atom.

• Remove electrons from the outer atoms.

How many additional electrons are added to the sulfate ion (SO4 2-) when calculating its total valence electrons?

• 3

• 2

• 1

• 4

For the phosphate ion (PO4 3-), how many extra valence electrons are added due to its charge?

• 4

• 3

• 2

• 1