Multiple Choice Questions'Hydride Gap' is referred to which region of the Periodic Table ?
Groups 3, 4 and 5
Groups 5, 6 and 7
Groups 4, 5 and 6
Groups 7, 8 and 9
The electronic configuration of the element with maximum electron affinity is
1s2, 2s2,2p3
1s2, 2s2,2p5
1s2, 2s2,2p6, 3s2, 3p5
1s2, 2s2,2p6, 3s2, 3p3
The first ionisation energy of oxygen is less than that of nitrogen. Which of the following is the correct reason for this observation?
Lesser effective nuclear charge of oxygen than nitrogen.
Lesser atomic size of oxygen than nitrogen
Greater interelectron repulsion between two electrons in the same p-orbital counter balances the increase in effective nuclear charge on moving from nitrogen to oxygen.
Greater effective nuclear charge of oxygen than nitrogen.
| Column I | Column II | ||
| (A) | He | (i) | High electron affinity |
| (B) | Cl | (ii) | Most electropositive element |
| (C) | Ca | (iii) | Strongest reducing agent |
| (D) | Li | (iv) | Highest ionisation energy |
A-iv, B-i, C-ii, D-iii
A-iii, B-i, C-ii, D-iv
A-iv, B-iii, C-ii, D-i
A-ii, B-iv, C-i, D-iii
A.
A-iv, B-i, C-ii, D-iii
(i) For noble gases (eg, He), ionisation energy is highest due to their completely filled electronic configuration.
(ii) Generally electron affinity increases in a period (from IA to VII A group) and decreases in a group but electron affinity is highest for chlorine (Cl) (due to smaller size and high electron density of fluorine).
(iii) The ionisation energy is lowest for Li, so it can lose electrons very easily, thus it behaves as a strongest reducing agent.
(iv) Electropositive character generally decreases in a period (from left to right) and increases in a group (on moving down), thus Ca is the most electropositive element among the given.
Hence, on the basis of above facts, the correct matches are
(A)-iv (B)-i (C)-ii (D)-iii
The lattice enthalpy and hydration enthalpy of four compounds are given below
| Compound | Lattice enthalpy (in kJ mol-1) | Hydration enthalpy (in kJ mol-1) |
| P | +780 | -920 |
| Q | +1012 | -812 |
| R | +828 | -878 |
| S | +632 | -600 |
The pair of compound which is soluble in water is
P and R
Q and R
P and Q
Rand S
In which of the following the oxidation number of oxygen has been arranged in increasing order?
OF2 < KO2 < BaO2 < O3
BaO2 < KO2 < O3 < OF2
BaO2 < O3 < OF2 < KO2
KO2 < OF2 < O3 < BaO2
In which one of the following pairs the radius of the second species is greater than that of the first?
Na, Mg
O2-, N3-
Li+, Be2+
Ba2+, Sr2+
Consider the ions : K+, S2-, Cl- and Ca2+. The radii of these ionic species follow the order
Ca2+ > K+ > Cl- > S2-
Cl- > S2- > K+ > Ca2+
S2- > Cl- > K+ > Ca2+
Ca2+ > S2- > Cl- > Ca2+
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