Comprehension given below is followed by some multiple choice questions. Each question has one correct option. Choose the correct option.

In the modern periodic table, elements are arranged in order of increasing atomic numbers which is related to the electronic configuration. Depending upon the type of orbitals receiving the last electron, the elements in the periodic table have been divided into four blocks, viz, s, p, d and f. The modern periodic table consists of 7 periods and 18 groups. Each period begins with the filling of a new energy shell. In accordance with the Arfbau principle, the seven periods (1 to 7) have 2, 8, 8, 18, 18, 32 and 32 elements respectively. The seventh period is still incomplete. To avoid the periodic table being too long, the two series of f-block elements, called lanthanoids and actinoids are placed at the bottom of the main body of the periodic table.

(a) The element with atomic number 57 belongs to

(i) s-block

(ii) p-block

(iii) d-block

(iv) f-block

The element expected to form largest ion to achieve the nearest noble gas configuration is:
<!-- [if !supportLineBreakNewLine]-->
<!--[endif]-->

The order of electron gain enthalpy in kJ/mol of fluorine, chlorine, bromine and iodine, respectively are
<!-- [if !supportLineBreakNewLine]-->
<!--[endif]-->

The correct order of the ionic radii of O²⁻, N³⁻, F⁻, Mg²⁺, Na⁺ and Al³⁺ is:

3.31. The first (ΔiH₁) and the second (ΔiH₂) ionization enthalpies (in kJ mol^–1) and the (Δ_egH) electron gain enthalpy (in kJ mol^–1) of a few elements are given below:

Elements      ΔH1      ΔH2       Δ_egH

I                    520       7300      –60

II                  419        3051     –48

III               1681        3374     –328

IV               1008        1846     –295

V                 2372       5251       +48

VI                 738       1451        –40

Which of the above elements is likely to be:

(a) The least reactive element

(b) The most reactive metal

(c) The most reactive non-metal

(d) The least reactive non-metal

(e) The metal which can form a stable binary halide of the formula MX₂ (X = halogen)

(f) The metal which can form a predominantly stable covalent halide of the formula MX (X = halogen)?

Electronic configuration of some elements is given in Column I and their electron gain enthalpies are given in Column II. Match the electronic configuration with electron gain enthalpy.