Скачать или смотреть First ionisation enthalpy values of the first four group 15 elements are given below. Choose the cor

Ionisation enthalpy, periodic trends, and phosphorus chemistry are the primary concepts associated with this question. Ionisation enthalpy is the energy required to remove the outermost electron from an isolated gaseous atom. In the periodic table, group 15 elements (N, P, As, Sb, Bi) have relatively high ionisation enthalpies due to their stable half-filled p-orbitals. Among them, phosphorus is notably important in biological and geological systems, particularly in compounds like phosphates, which are the main constituents of apatite minerals.

The apatite family includes minerals like fluorapatite and hydroxyapatite, which are rich in phosphorus. Phosphorus occurs widely in nature in the form of phosphates, making it essential in bone and tooth mineral composition in vertebrates. Phosphorus has a first ionisation enthalpy of about 1012 kJ/mol, which helps distinguish it from other group 15 elements in multiple-choice formats. This property reflects its place in the periodic table and its electron configuration (3s²3p³).

Periodic variation in ionisation enthalpy for group 15 shows a decrease down the group: nitrogen greater than phosphorus greater than arsenic greater than antimony greater than bismuth. The trend corresponds to increasing atomic size and shielding effect. Since phosphorus is the second element in group 15 and forms a major component of the apatite family, identifying it requires both knowledge of its chemical importance and its ionisation energy within the group trend.

Question Statement:

First ionisation enthalpy values of the first four group 15 elements are given below. Choose the correct value for the element that is a main component of the apatite family:
(1) 1402 kJ mol⁻¹
(2) 834 kJ mol⁻¹
(3) 1012 kJ mol⁻¹
(4) 947 kJ mol⁻¹