16 Oxidation Numbers MCQ2

Oxidation Numbers

• The oxidation number is the charge an atom appears to have when electrons are distributed according to certain rules.
• Uncombined elements have an oxidation number of zero.

Rules for Assigning Oxidation Numbers

• The sum of oxidation numbers in a molecule is zero.
• The oxidation number of an ion of an element is the same as its charge.
• The sum of the oxidation numbers of all atoms in a complex ion equals the charge on that ion.

Oxidation Numbers of Specific Elements

• Hydrogen has an oxidation number of +1 when bonded.
• Oxygen has an oxidation number of -2, except in peroxides where it's -1, and when bonded to fluorine, it's +2.
• Group 1 elements have an oxidation number of +1 in compounds.
• Group 2 elements have an oxidation number of +2 in compounds.
• Halogens have an oxidation number of -1 when bonded to a less electronegative atom.

Transition Metal Oxidation States

• Chromium: +2, +3, +6
• Manganese: +2, +3, +4, +6, +7
• Iron: +2, +3, +6
• Copper: +1, +2