Oxidation Numbers in Compounds

The video tutorial explains how to determine the oxidation number for mercury in mercury(II) oxide (HgO). It begins by noting that HgO is a neutral compound, meaning the sum of its oxidation numbers is zero. Oxygen typically has an oxidation number of -2. Since the compound is neutral, mercury must have an oxidation number of +2 to balance the -2 from oxygen. The video concludes with a calculation showing that the sum of +2 (mercury) and -2 (oxygen) equals zero, confirming the oxidation numbers.

What is the overall charge of a neutral compound like HgO?

• Depends on the elements

• Positive

• Zero

• Negative

What is the typical oxidation number assigned to oxygen in compounds?

• -2

• +2

• 0

• +1

Why is the oxidation number of mercury in HgO +2?

• Because mercury is a noble gas

• To balance the -2 from oxygen

• To make the compound positively charged

• Because mercury is always +2

In the compound HgO, what must the sum of the oxidation numbers equal?

• +1

• -2

• +2

• 0

Which element in HgO is a transition metal that can have different oxidation states?

• Oxygen

• Carbon

• Mercury

• Hydrogen