Oxidation Numbers and States

The video tutorial explains the concept of oxidation numbers, particularly focusing on elements with the same electronegativity, such as O2, where the oxidation number is zero. It highlights the importance of understanding oxidation states when balancing redox reactions. The tutorial also covers how oxidation numbers are assigned in compounds with different elements, like H2O and SO3, and explains why O2 has a zero oxidation number due to equal attraction between atoms. Additionally, it discusses oxidation numbers for uncombined elements and ions, using examples like copper ions.

What is the oxidation state of O2 in a compound where elements have the same electronegativity?

• -2

• +1

• 0

• +2

Which of the following is an example of a free element with an oxidation state of zero?

• SO3

• Cu2+

• Na

• H2O

Which of the following elements would have an oxidation state of zero when uncombined?

• Cu2+

• SO3

• Fe

• H2O

What is the oxidation state of a neutral element like Na?

• 0

• +1

• -1

• +2

What happens to the oxidation number when elements are not combined?

• It becomes positive

• It becomes undefined

• It remains zero

• It becomes negative

Why do compounds like O2 have an oxidation number of zero?

• Because they have different elements

• Because they are always oxidized

• Because they have the same electronegativity

• Because they are ions

In a chemical bond, which atom is assumed to have a stronger attraction on the bonding pair of electrons?

• The atom with a positive charge

• The atom with a negative charge

• The less electronegative atom

• The more electronegative atom

How do atoms in O2 share electrons?

• Equally, with no positive or negative oxidation number

• Equally, with both atoms having a positive oxidation number

• Unequally, with one atom having a negative oxidation number

• Unequally, with one atom having a positive oxidation number

What is the oxidation number of copper in Cu2+?

• -2

• +2

• 0

• +1

Which of the following statements is true about ions?

• Ions have no oxidation number

• Ions have an oxidation number equal to their charge

• Ions have an oxidation number of -1

• Ions always have an oxidation number of zero