NEED HELP! URGENT! WILL MARK BRAINLIEST What is the oxidation number for “O” in ErO₂ ?
A. -6
B. -1
C. -4
D. 4
E. 2
-2
What is the oxidation number for “Er” in ErO₂ ?
A. -4
B. -2
C. +1
D. +2
E. +4

What is the oxidation number for “At” in AtO₃⁻ ?
A. +5
B. +7
C. -2
D. +3
E. -6

What is the oxidation number for “O” in AtO₃⁻ ?
A. -6
B. -4
C. +4
D. -2
E. -3
F. +2