Which of the following isoelectronic species has the largest radius?

1.  $K^{+}$

2.  $C{a^2}^{+}$

3.  $P^{3-}$

4.  $S^{2-}$

Which group best illustrates the transition from non-metallic behavior with increasing atomic number?

1.  Be, Mg, Ca, Sr

2.  N, P, As, Sb

3.  F, Cl, Br, l

4.  Fe, Ru, Os, Hs

What property of the oxygen atom is represented by the equation : $O\left(g\right)+e^{-}\to O^{-}\left(g\right)$?

1.  Electronegativity

2.  First electron affinity

3.  First ionization energy

4.  Lattice energy

In which list are atoms of the elements Be, B, Mg and Al arranged from smallest to largest atomic radius?

1.  Be < B < Mg < Al

2.  Mg < Be < Al < B

3.  B < Be < Al < Mg

4.  Al < Mg < B < Be

Which gas-phase atom has the largest radius?

1.  Na

2.  K

3.  Mg

4.  Ca

Based on its position in the periodic table, element 114 is most likely to be a

1.  Reddish-brown volatile liquid

2.  A pale yellow-green gas

3.  A colourless crystal

4.  A grey-silvery metal

Which of the following pairs of substances are allotropes?

1. ${\mathrm{CH}}_3{\mathrm{CH}}_2\mathrm{OH} \mathrm{and} {\mathrm{CH}}_3{\mathrm{OCH}}_3$

2. $\mathrm{Fe}{\left({\mathrm{NO}}_3\right)}_2 \mathrm{and} \mathrm{Fe}{\left({\mathrm{NO}}_3\right)}_3$

3. NaCl and KCl

4. ${\mathrm{O}}_2 \mathrm{and} {\mathrm{O}}_3$

What is the general trend observed for the first ionization energies of the elements in groups 13 to 17?

1. Ionization energies tend to increase from left to right in a period and are approximately constant in a group

2. Ionization energies tend to increase from left to right in a period and decrease from top to bottom in a group

3. Ionization energies tend to decrease from left to right in a period and increase from top to bottom in a group

4. Ionization energies tend to decrease from left to right a period and decrease from top to bottom in a group

Which of the following statements is not correct?

1.  The first ionization energy generally decreases from top to bottom within a group

2.  The atomic radius generally increases from top to bottom within a group

3.  The first ionization energy generally decreases from left to right across a period

4.  The second ionization energy of an atom is always greater than the first ionization energy

One element has atomic weight 39. Its electronic configuration is 1s² 2s² 2p⁶ 3s² 3p⁶ 4s¹. The true statement for this element is: 

1. High value of IE                               

2. Transition element

3. Isotone with \(^{38}_{18} A r\)   $$

4. None of the above