pure atoms are assigned ____
0
all monatomic ions have oxidation numbers equal to ____
their charges (group 1 = +1, group 2 = +2)
flourine is always ___ in its compound
-1
halogens are usually ____
-1
halogens are usually (n), except ______
when they’re central or combined with a more e-neg element (eg. +3 in ICl3 and -1 in NI3))
oxygen is ____ in most compounds
-2
oxygen is (n) in most compounds, except ____
peroxides (H2O2, Na2O2) where it is -1
hydrogen is usually ____
+1
hydrogen is usually (n), except _______
hydrides with electropositive elements, especially metal cations, where it is -1 (NaH, CaH2)
the sum of all in a neutral compound is _____
0
for a polyatomic ion, the sum is _____
the charge of the species (ClO3 = -1; O = -2, Cl = +1)