Which of the following group 15 elements has the greatest metallic character?
(1) nitrogen (3) antimony
(2) phosphorus (4) bismuth

The answer is no. 4. Bismuth (Bi)
Across the period, from left to right, metallic character decreases, meaning, when it is going down, the last element in a group will have the most metallic character. Since Bismuth (bi) is the last element, it is the most metallic. The arrangement of the group 15 elements in ascending rate of metallic character is: N (Nitrogen) P (Phosphorus), As (Arsenic), Sb (Antimony) and Bi (Bismuth). Bismuth has the lowest rate of electronegativity and ionization energy thus, it is more likely to lose an e- than the rest of the elements of the said group, which is why it is considered the most metallic.

60.0 - there are 3 significant numbers

☆ionisation energy increases across a period from na -> ar☆ionisation energy decreases down a group from li -> fr☆ionic radius decreases across a period from na -> cl☆ionic radius increases down a groupfrom f -> ii hope it clarifies your doubts