Question

Which of the following is a favourable factor for cation formation?
(A) Low ionisation potential
(B) High electron affinity
(C) High electronegativity
(D) Small atomic size

Answer 1

Hint: Cations are the positive ions formed by the loss of one or more electrons. The most commonly formed cations are those which involve the loss of all of the valence electrons.

Complete step by step solution:
Cations are generally known as positively charged atoms. Consider the alkali metal sodium (Na). It has one valence electron in the third principal energy level like the E.C. of Na is \[1{{s}^{2}}2{{s}^{2}}2{{p}^{6}}3{{s}^{1}}\]which by the loss of one electron form \[N{{a}^{+}}\]ion which is a called as a cation.
(A) Low ionisation potential: It is also known as ionization energy; the energy required to remove the most loosely bound electrons from an atom to form a positive ion. During the formation of an ionic bond, one atom must form a cation by losing one or more electrons. In general, elements having low ionization energies have a more favourable chance to form a cation.
(B) High electron affinity: It is the amount of energy released when an atom accepts an electron to form a negative ion. Higher electron affinity favours the formation of an anion.
(C) High electronegativity: Electronegativity measures the tendency of an atom to attract a shared pair of electrons. Higher the electronegativity more is the attraction of electrons.
(D) Small atomic size: Atomic size of the elements decreases as we move from left to right and increases as we move from top to bottom.

Thus, (A) is the right answer.

Note: There are two types of ions present in the compounds; Cations and anions in which cation are those compounds which formed by a general loss of electrons and contain positive charge on the other hand anion are negatively charged atoms formed by gaining electrons.