Oxidation Numbers and Free Elements

The video explains the oxidation number for phosphorus in P4, an allotrope of phosphorus. It highlights that free elements, like P4, have an oxidation number of zero. The video also discusses how in neutral compounds, the oxidation numbers must sum to zero, which is why each phosphorus atom in P4 has an oxidation number of zero.

What is the main focus of the video regarding oxidation numbers?

• Oxidation numbers in carbon compounds

• Oxidation numbers in metals

• Oxidation numbers in P4

• Oxidation numbers in water

Which of the following is considered a free element with an oxidation number of zero?

• CO2

• P4

• H2O

• NaCl

Why is P4 considered a free element?

• It is a compound with multiple elements

• It is a neutral compound

• It is a charged ion

• It is a mixture of gases

What must the sum of oxidation numbers in a neutral compound equal?

• Zero

• One

• Positive one

• Negative one

What is the oxidation number of each phosphorus atom in P4?

• One

• Negative three

• Zero

• Positive three