It is the outermost electrons, for example all the first line has one outer electron and the second has to and so on and so forth. BUT THE TRANSITION METALS FOLLOW A DIFFERENT RULE.
D. Should be correct- the other ones don’t make sense
Answer:
33.33 h
Explanation:
You know that
1 h = 60 min
If you divide both sides by 60 min, you get the conversion factor: 1 h/60 min = 1.
If you divide both sides by 1 h, you get the conversion factor: 1 = 60 min/1 h.
Both are conversion factors because they both equal one and multiplying a measurement by one does not change its value.
You choose the conversion factor that gives you the correct dimensions for your answer. It must have the correct dimensions on top (in the numerator),
Thus, to convert 2000 min to hours, you use the conversion factor with “h” on the top.

CaI₂ + Hg(NO₃)₂ --------->HgI₂ + Ca(NO3)2
2Al + 3Cl₂ --------->2AlCl3
Ag + HCl ------->AgCl + H2
C2H2 + 5O2 --------> 4CO2 + 2H2O
MgCl₂ --------->Mg + Cl2