Question

1. samples of four group 15 elements, antimony, arsenic, bismuth, and phosphorus, are in the gaseous phase. an atom in the ground state of which element requires the least amount of energy to remove its most loosely held electron?
2. as
3. bi
4. p
5. sb
6. which of the following elements has the most pronounced metallic characteristics?
7. c
8. co
9. al
10. rb

Explanation:

13. Ionization energy trend

Ionization energy (the energy required to remove an electron) decreases down a group. In Group 15 (N, P, As, Sb, Bi), as we go from P (higher up in the group) to Bi (lower down), the atomic size increases. With larger atomic size, the out - ermost electrons are less tightly held by the nucleus. So, Bi has the least ionization energy among the given Group 15 elements (As, P, Bi, Sb).

14. Metallic character trend

Metallic character increases down a group and decreases across a period from left to right.

• C (carbon) is a non - metal.
• Al (aluminium) is a metal but has some non - metallic properties (amphoteric).
• Co (cobalt) is a transition metal.
• Rb (rubidium) is an alkali metal. Alkali metals are highly metallic. As we move down the groups in the s - block, the metallic character increases. Rb is in Group 1 (more metallic than Group 13 Al) and is more metallic than Co (transition metal) and C (non - metal).

Answer:

1. 2) Bi
2. 4) Rb