Oxidation Numbers and Ionic Charges

The video tutorial explains how to determine the oxidation numbers for each element in aluminum hydroxide (Al(OH)3). It begins by stating that the compound is neutral, meaning the oxidation numbers must sum to zero. The video outlines two methods: the first involves assigning oxidation numbers based on known values for oxygen and hydrogen, while the second uses the hydroxide ion's charge. Both methods conclude that aluminum has an oxidation number of +3. The tutorial is presented by Dr. B, who summarizes the findings at the end.

What does the absence of a charge sign after Al(OH)3 indicate about the compound?

• It is an unstable compound.

• It is a positively charged compound.

• It is a neutral compound.

• It is a negatively charged compound.

What is the typical oxidation number for oxygen in compounds, except when bonded to fluorine or in peroxides?

• +2

• -2

• 0

• +1

When hydrogen is bonded to nonmetals, what is its usual oxidation number?

• +1

• +2

• -1

• 0

How do the oxidation numbers of oxygen and hydrogen in Al(OH)3 combine to affect the overall charge?

• They result in a fluctuating charge.

• They result in a neutral charge.

• They result in a positive charge.

• They result in a negative charge.

What must be the oxidation number of aluminum in Al(OH)3 for the compound to remain neutral?

• +1

• +2

• +3

• 0

What is the ionic charge of the hydroxide ion (OH) in Al(OH)3?

• +2

• 0

• -1

• +1

How do the oxidation numbers in the hydroxide ion add up to its ionic charge?

• They add up to +2.

• They add up to 0.

• They add up to -1.

• They add up to +1.

What is the overall oxidation number of the elements in Al(OH)3 when using the hydroxide ion method?

• +1

• -3

• 0

• +3