Understanding Oxidation Numbers

This video tutorial covers the rules for assigning oxidation numbers to elements in compounds and ions. It explains the importance of oxidation numbers in chemistry and provides detailed rules for calculating them in neutral compounds, ions, free elements, and specific cases involving fluorine, hydrogen, and oxygen. The video emphasizes the distinction between oxidation numbers and ionic charges and offers practice exercises to reinforce learning.

What is the sum of oxidation numbers in a neutral compound?

• Always positive

• Always negative

• Zero

• Depends on the compound

In the sulfate ion (SO4^2-), what is the oxidation number of sulfur?

• -2

• 0

• +6

• +4

How do oxidation numbers and ionic charges differ?

• Oxidation numbers are always positive

• They are always the same

• They can differ for the same element

• Ionic charges are always negative

What is the oxidation number of a free element?

• +1

• Depends on the element

• 0

• -1

What is the oxidation number of fluorine in compounds?

• +1

• -1

• 0

• +2

What is the oxidation number of elements in Group 1 of the periodic table?

• -1

• +1

• +2

• 0

In sodium peroxide (Na2O2), what is the oxidation number of oxygen?

• +1

• 0

• -1

• -2

When hydrogen is bonded to metals, what is its oxidation number?

• -1

• +2

• +1

• 0

What is a common exception to the rule that oxygen has an oxidation number of -2?

• In sulfates

• When bonded to hydrogen

• In peroxides

• In nitrates

What is the oxidation number of chlorine in ClO3^-?

• 0

• +3

• -1

• +5