Oxidation Numbers and Ionic Charges

This video tutorial explains how to determine the oxidation numbers for elements in copper(II) sulfide (CuS). It begins by identifying CuS as a neutral compound, meaning the oxidation numbers must sum to zero. The video then explains that sulfur, being more electronegative, takes an oxidation state of -2. Consequently, copper must have an oxidation state of +2 to balance the compound. The tutorial concludes by summarizing these findings.

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

• Zero

• Negative

• Depends on the elements

• Positive

Which element in a binary compound is assigned an oxidation number equal to its ionic charge?

• The more electropositive element

• The more electronegative element

• The element with a higher atomic number

• The element with a lower atomic number

In which group of the periodic table is sulfur found, and what is its typical ionic charge?

• Group 15, 3-

• Group 16, 2-

• Group 17, 1-

• Group 14, 4+

What oxidation number is assigned to sulfur in CuS?

• 0

• 1-

• 2-

• 3-

What must be the oxidation number of copper in CuS to balance the compound?

• 2+

• 1+

• 3+

• 4+

Why do the oxidation numbers in a neutral compound like CuS add up to zero?

• Because it contains only nonmetals

• Because it is a binary compound

• Because it is a transition metal compound

• Because it has no net charge