Oxidation Numbers in Compounds

The video tutorial explains how to find the oxidation numbers for each element in potassium sulfide (K2S). It begins by noting that K2S is a neutral compound, meaning the oxidation numbers must sum to zero. Potassium, being in group one of the periodic table, has a +1 oxidation number. With two potassium atoms, the total is +2. To balance this, sulfur must have a -2 oxidation number. The video concludes by confirming these calculations and summarizing the oxidation numbers for K2S.

What is the total sum of oxidation numbers in a neutral compound like K2S?

• It is always positive.

• It is always negative.

• It is zero.

• It varies depending on the compound.

Which group in the periodic table does potassium belong to, and what is its typical oxidation number?

• Group 1, +1

• Group 2, +2

• Group 16, -2

• Group 17, -1

How many potassium atoms are present in K2S, and what is their combined oxidation number?

• Two potassium atoms, +2

• Two potassium atoms, +1

• One potassium atom, +1

• One potassium atom, +2

What is the oxidation number of sulfur in K2S?

• 0

• +2

• -1

• -2

Why must sulfur have a -2 oxidation number in K2S?

• Because sulfur is always -2.

• To balance the +2 from potassium and achieve a total of zero.

• To make the compound positively charged.

• To make the compound negatively charged.

What is the role of oxidation numbers in determining the charge of a compound?

• They help in balancing chemical equations.

• They are used to calculate the molecular weight.

• They determine the physical state of the compound.

• They indicate the total charge of the compound.