The correct order of the decreasing ionic radii among the following isoelectronic species is:
1.
2.
3.
4.
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 |
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
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. \(1 s^2 2 s^2 2 p^6\)
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
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. |
The correct order of ionic radii is:
1.
2.
3.
4.
The formation of the oxide ion O2- (g), from the oxygen atom requires first an exothermic and then an endothermic step as shown below,
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. |
Magnesium reacts with an element (X) to form an ionic compound.
If the ground state electronic configuration of (X) is ,
the simplest formula for this compound is:
1.
2.
3.
4.
Element of the third period that is expected to exhibit positive electron gain enthalpy is:
1. | Na | 2. | Al |
3. | Cl | 4. | Ar |