Concept:Metallic character increases down a group and decreases from left to right across a period.
Valence electrons for main-group elements equal their group number (for groups 1, 2, and 13–18).
Explanation:We are given six elements:
N,
P,
O,
S,
Cl, and
F.
Metallic character is highest at the bottom-left of the periodic table.
Among these,
P (period 3, group 15) is the lowest and leftmost: it is the most metallic.
P belongs to group 15, so it has
5 valence electrons.
Non-metallic character is highest at the top-right of the periodic table.
Among the given,
F (period 2, group 17) is the highest and rightmost: it is the least metallic (most non-metallic).
F belongs to group 17, so it has
7 valence electrons.
Therefore, the number of valence electrons for the most metallic and least metallic elements are
5 and
7, respectively.
Shortcut:Most metallic among given = lowest in group, leftmost in period →
P (group 15, valence 5).
Least metallic = highest in group, rightmost in period →
F (group 17, valence 7).
For main-group elements, valence electrons = group number (for groups 13–18, subtract 10).
Answer:5 and
7 Option C: 5 and 7