Question

Discuss the general characteristics of group 15 elements with reference to their electronic configuration, oxidation state, atomic size, ionization enthalpy, and electronegativity.

Answer 1

Group 15 elements are also known as the nitrogen family so the elements of the group are nitrogen, phosphorus, arsenic, antimony, and bismuth. This group is the third group in the p-block.

Complete step by step answer:
-Elements of group 15 are known as the nitrogen family and they are the third group of the p-block. The members of this group are nitrogen, phosphorus, arsenic, antimony, and bismuth.
-The atomic number of nitrogen is 7 so its electronic configuration is $1{{s}^{2}}2{{s}^{2}}2{{p}^{3}}$. The atomic number of phosphorus is 15 so its electronic configuration is $1{{s}^{2}}2{{s}^{2}}2{{p}^{6}}3{{s}^{2}}3{{p}^{3}}$. The atomic number of Arsenic is 33 so its electronic configuration is $1{{s}^{2}}2{{s}^{2}}2{{p}^{6}}3{{s}^{2}}3{{p}^{6}}3{{d}^{10}}4{{s}^{2}}4{{p}^{3}}$. The atomic number of Antimony is 51 so its electronic configuration is $1{{s}^{2}}2{{s}^{2}}2{{p}^{6}}3{{s}^{2}}3{{p}^{6}}3{{d}^{10}}4{{s}^{2}}4{{p}^{6}}4{{d}^{10}}5{{s}^{2}}5{{p}^{3}}$. The atomic number of Bismuth is 83 so its electronic configuration is $1{{s}^{2}}2{{s}^{2}}2{{p}^{6}}3{{s}^{2}}3{{p}^{6}}3{{d}^{10}}4{{s}^{2}}4{{p}^{6}}4{{d}^{10}}5{{s}^{2}}5{{p}^{6}}5{{d}^{10}}6{{s}^{2}}6{{p}^{3}}$. So the general electronic configuration of group 15 can be written as $n{{s}^{2}}n{{p}^{3}}$
-So group 15 elements have 5 valence electrons they can show both positive and negative oxidation states. Nitrogen can show -3, -2, -1, +3, and +5. Phosphorus show -3, -2, +3, and +5. Arsenic, antimony, and bismuth show -3, +3, and +5 oxidation states.
-As we can see that the electronic configuration, the number of electrons increases so the number of shells increases, and the distance increases, therefore the atomic size increases as we move down.
-As the p-subshell has exactly half-filled, so they have extra stability, hence their ionization enthalpy is higher than group 14. So as the size increases down the group due to an increase in the number of a subshell, the ionization enthalpy decreases. The electronegativity of group 15 is higher than group 14 and lower than group 16. So as the size increases down the group due to an increase in the number of a subshell, the electronegativity decreases.

Note: The same trend is followed for ionic radii as the atomic size of the group 15 elements. As we move down the group the non-metallic character of group 15 decreases or we can say that bismuth is a metal.