What element's don't have oxidation numbers?

• alkali metals
• noble gases
• halogens
• alkaline earth metals

What is the oxidation number of Ca?

• +3

• +2

• -3

• -2

What is the oxidation number of S ?

• -2

• +2

• +6

• -4

What is oxidation number of P ?

• +1

• -3

• -2

• 0

What are oxidation numbers?

• Number of electrons in the outer most energy level

• Number of protons

• The charge of an atom when electrons are gained or lost

• Number of neutrons gained or lost

What are valence electrons?

• Number of electrons in the outer most energy level
• Number of electrons gained or lost
• Number of electrons in the inner energy level
• Number of electrons 

What is the oxidation number of O ?

• +2

• -1

• +4

• -2

What is the oxidation number of N ?

• -3

• +4

• -2

• +3

What is the oxidation state of Cl ?

• 0

• +1

• -1

• +2

What is the oxidation state of Cu in Cu²⁺?

• -1

• -2

• +2

• 0