Answer:
because they need only one electron
Sodium has 1 valence electron and chlorine has 7 valence electrons and the goal is to get t 8 valence electrons then they attract together, forming table salt.
Answer:
b) +2 and +3.
Explanation:
Hello,
In this case, given the molecular formulas:

And:

We can relate the subscripts with the oxidation states by knowing that they are crossed when the compound is formed, for that reason, we notice that oxygen oxidation state should be -2 for both cases and the oxidation state of X in the first formula must be +2 since both X and O has one as their subscript as they were simplified:

Moreover, for the second case the oxidation state of X should be +3 in order to obtain 3 as the subscript of oxygen:

Thus, answer is b)+2 and +3
Best regards.
Solution here,
Volume(V)=67.4 L
Pressure(P)=1 atm
Temperature(T)=(0+273)K=273K
Universal gas constant(R)=0.0821 L.atm.mol^-1K^-1
No. of moles(n)=?
Now,
PV=nRT
or, 1×67.4=n×0.0821×273
or, 67.4=22.4n
or, n=67.4/22.4
or, n=3
therefore, required no. of mole is 3.