The correct order of increasing electron affinity for the elements, O, S, F and Cl is:

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

Subtopic:  Electron Affinity (EA) |
 77%
From NCERT
AIPMT - 2010
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Among the following, the most characteristic oxidation states for lead and tin are, respectively:

1. +4, +2

2. +2, +4

3. +4, +4

4. +2, +2

Subtopic:  Electronic Configuration |
 63%
From NCERT
AIPMT - 2007
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A configuration with the lowest ionization enthalpy among the following is:
1. \(1 s^2 2 s^2 2 p^5\)\(1 s^2 2 s^2 2 p^5\)
2. \(1 s^2 2 s^2 2 p^3\)
3. \(1 s^2 2 s^2 2 p^6 3 s^1\)
4. \(1 s^2 2 s^2 2 p^6\)

Subtopic:  Ionization Energy (IE) |
 78%
From NCERT
AIPMT - 2007
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For the second-period elements, the correct increasing order of first ionisation enthalpy is:

1. Li < Be < B < C < O < N < F < Ne
2. Li < Be < B < C < N < O < F < Ne
3. Li < B < Be < C < O < N < F < Ne
4. Li < B < Be < C < N < O < F < Ne
Subtopic:  Ionization Energy (IE) |
 75%
From NCERT
NEET - 2019
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The correct order of the decreasing ionic radii among the following isoelectronic species is:

1. Ca2+>K+>S2->Cl-

2. Cl->S2->Ca2+>K+

3. S2->Cl->K+>Ca2+

4. K+>Ca2+>Cl->S2-

Subtopic:  Atomic Size |
 88%
From NCERT
AIPMT - 2010
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The incorrect order of electronegativity is :

1. Cl > S > P > Si 2. Si > Al > Mg > Na
3. F > Cl > Br > I 4. None of the above.
Subtopic:  Electronegativity |
 63%
From NCERT
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The correct order of ionic radii is:

1. H->H+>H 
2. Na+>F->O2-
3. F->O2->Na+
4. N3->Mg2+>Al3+

Subtopic:  Atomic Size |
 81%
From NCERT
AIPMT - 2014
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The formation of the oxide ion O2– (g), from the oxygen atom requires first an exothermic and then an endothermic step as shown below, 
Og+e-O-; fH0=141 kJ mol-1
O-g+e-O2-g; fH0=+780 kJ mol-1

Thus, the process of formation of O2– in the gas phase is unfavorable even though O2– is isoelectronic with neon. It is due to the fact that:

1. Electron repulsion outweighs the stability gained by achieving noble gas configuration.
2. O ion has a comparatively smaller size than the oxygen atom.
3. Oxygen is more electronegative.
4. Addition of electrons in oxygen results in a large size of the ion.
Subtopic:  Electron Affinity (EA) |
 75%
From NCERT
NEET - 2015
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Magnesium reacts with an element (X) to form an ionic compound. If the ground state electronic configuration of (X) is 1s22s22p3, the simplest formula for this compound is: 

1. Mg2X3

2. MgX2

3. Mg2X

4. Mg3X2

Subtopic:  Nature of Compound |
 74%
From NCERT
NEET - 2018
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Element of the third period that is expected to exhibit positive electron gain enthalpy is: 

1. Na 2. Al
3. Cl 4. Ar
Subtopic:  Electron Affinity (EA) |
 68%
From NCERT
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