Chemistry

The elements in which electrons are progressively filled in 4f-orbital are called

(i) Actinoids

(ii) Transition elements

(iii) Lanthanoids

(iv) Halogens

The period number in the long form of the periodic table is equal to

(i) Magnetic quantum number of any element of the period.

(ii) Atomic number of any element of the period.

(iii) Maximum Principal quantum number of any element of the period.

(iv) Maximum Azimuthal quantum number of any element of the period.

Among halogens, the correct order of amount of energy released in electron gain (electron gain enthalpy) is:

(i) F > Cl > Br > I

(ii) F < Cl < Br < I

(iii) F < Cl > Br > I

(iv) F < Cl < Br < I

The statement that is not correct for periodic classification of elements is:

(i) The properties of elements are periodic function of their atomic numbers.

(ii) Non metallic elements are less in number than metallic elements.

(iii) For transition elements, the 3d-orbitals are filled with electrons after 3p-orbitals and before 4s-orbitals.

(iv) The first ionisation enthalpies of elements generally increase with increase in atomic number as we go along a period.

The electronic configuration of gadolinium (Atomic number 64) is 

(i) [Xe] 4f ³ 5d⁵ 6s²

(ii) [Xe] 4f⁷ 5d² 6s¹

(iii) [Xe] 4f⁷ 5d¹ 6s²

(iv) [Xe] 4f⁸ 5d⁶ 6s²

The first ionisation enthalpies of Na, Mg, Al and Si are in the order:

(i)   Na < Mg > Al < Si

(ii)  Na > Mg > Al > Si

(iii) Na < Mg < Al < Si

(iv) Na > Mg > Al < Si

The first ionisation enthalpies of Na, Mg, Al and Si are in the order:

(i)   Na < Mg > Al < Si

(ii)  Na > Mg > Al > Si

(iii) Na < Mg < Al < Si

(iv) Na > Mg > Al < Si

The order of screening effect of electrons of s, p, d and f orbitals of a given shell of an atom on its outer shell electrons is:

(i) s > p > d > f

(ii) f > d > p > s

(iii) p < d < s > f

(iv) f > p > s > d

Which of the following is not an actinoid?

(i) Curium (Z = 96)

(ii) Californium (Z = 98)

(iii) Uranium (Z = 92)

(iv) Terbium (Z = 65)

Consider the isoelectronic species, Na⁺, Mg²⁺, F^– and O^2–. The correct order of increasing length of their radii is _________.

(i) F^- < O^2– < Mg²⁺ < Na⁺

(ii) Mg²⁺ < Na⁺ < F^– < O^2–

(iii) O^2– < F^– < Na⁺ < Mg²⁺

(iv) O^2– < F^– < Mg²⁺ < Na