Classification of Elements and Periodicity in Properties

Which of the following represents the correct order of increasing electron gain enthalpy with negative sign for the elements O, S, F and Cl ?

1. Cl < F < O < S
2. O < S < F < Cl
3. F < S < O < Cl
4. S < O < Cl < F

Amongst the elements with following electronic configurations, which one of them may have the highest ionisation energy ?

1. [Ne] 3s2 3p2
2. [Ar] 3d10 4s2 4p3
3. [Ne] 3s2 3p1
4. [Ne] 3s2 3p3

Identify the correct order of the size of the following:

1. Ca2+ < K+ < Ar < Cl- < S2-
2. Ar < Ca2+ < K+ < Cl- < S2-
3. Ca2+ < Ar < K+ < Cl- < S2-
4. Ca2+ < K+ < Ar < S2- < Cl-

With which of the following electronic configuration an atom has the lowest ionisation enthalpy?

1. 1s2 2s2 2p3
2. 1s2 2s2 2p6 3s1
3. 1s2 2s2 2p6
4. 1s2 2s2 2p5

Which of the following is the most basic oxide?

1. SeO2
2. Al2O3
3. Sb2O3
4. Bi2O3

Which one of the following arrangements represents the correct order of electron gain enthalpy (with negative sign) of the given atomic species ?

1. S < O < Cl < F
2. Cl < F < S < O
3. F < Cl < O < S
4. O < S < F < Cl

A nuclide of an alkaline earth metal undergoes radioactive decay by emission of three -particles in succession. The group of the periodic table to which the resulting daughter element would belong is

1. Gr. 13
2. Gr. 17
3. Gr. 14
4. Gr. 16

Ionic radii are

1. inversely proportional to effective nuclear charge
2. inversely proportional to square of effective nuclear charge
3. directly proportional to effective nuclear charge
4. directly proportional to square of effective nuclear charge.

The ions O2-, F-, Na+, Mg2+ and Al3+ are isoelectronic. Their ionic radii show

1. a significant increase from O2- to Al3+
2. a significant decrease from O2- to Al3+
3. an increase from O2- to F- and then decrease from Na+ to Al3+
4. a decrease from O2- to F- and then increase from Na+ to Al3+

Which of the following is isoelectronic?

1. CO2, NO2
2. NO2-, CO2
3. CN-, CO
4. SO2, CO2