Assign the position of the element having outer electronic configuration (iii) $(n-2) f^{7} (n-1)d^{1}ns^{2}$ for $n=6$, in the periodic table.

What are the major differences between metals and non-metals?

Predict the formulas of the stable binary compounds that would be formed by the combination of the following pairs of elements. (a) Lithium and oxygen

Among the second period elements the actual ionization enthalpies are in the order $Li < B < Be < C < O < N < F < Ne$. Explain why (ii) $O$ has lower $\Delta_{i} H$ than $N$ and $F$?

Considering the elements $B$, $C$, $N$, $F$, and $Si$, the correct order of their non-metallic character is :

The first ionization enthalpy values (in $kJ mol^{-1}$) of group 13 elements are :
B Al Ga In Tl
801 577 579 558 589
How would you explain this deviation from the general trend ?

Which one of the following statements is incorrect in relation to ionization enthalpy?

What do you understand by isoelectronic species? Name a species that will be isoelectronic with each of the following atoms or ions. (iii) $Mg^{2+}$

The first ($\Delta_{i}H_{1}$) and the second ($\Delta_{i}H_{2}$) ionization enthalpies (in kJ $mol^{-1}$) and the ($\Delta_{eg}H$) electron gain enthalpy (in kJ $mol^{-1}$) of a few elements are given below:
Elements $\Delta H_{1}$ $\Delta H_{2}$ $\Delta_{eg}H$
I 520 7300 –60
II 419 3051 –48
III 1681 3374 –328
IV 1008 1846 –295
V 2372 5251 +48
VI 738 1451 –40
Which of the above elements is likely to be : (f) the metal which can form a predominantly stable covalent halide of the formula $MX$ ($X$=halogen)?

Considering the elements $B$, $Al$, $Mg$, and $K$, the correct order of their metallic character is :

Which element do you think would have been named by (ii) Seaborg’s group?

Which of the following pairs of elements would have a more negative electron gain enthalpy? (i) $O$ or $F$

Which important property did Mendeleev use to classify the elements in his periodic table and did he stick to that?

The first ($\Delta_{i}H_{1}$) and the second ($\Delta_{i}H_{2}$) ionization enthalpies (in kJ $mol^{-1}$) and the ($\Delta_{eg}H$) electron gain enthalpy (in kJ $mol^{-1}$) of a few elements are given below:
Elements $\Delta H_{1}$ $\Delta H_{2}$ $\Delta_{eg}H$
I 520 7300 –60
II 419 3051 –48
III 1681 3374 –328
IV 1008 1846 –295
V 2372 5251 +48
VI 738 1451 –40
Which of the above elements is likely to be : (e) the metal which can form a stable binary halide of the formula $MX_{2}$($X$=halogen).

The first ($\Delta_{i}H_{1}$) and the second ($\Delta_{i}H_{2}$) ionization enthalpies (in kJ $mol^{-1}$) and the ($\Delta_{eg}H$) electron gain enthalpy (in kJ $mol^{-1}$) of a few elements are given below:
Elements $\Delta H_{1}$ $\Delta H_{2}$ $\Delta_{eg}H$
I 520 7300 –60
II 419 3051 –48
III 1681 3374 –328
IV 1008 1846 –295
V 2372 5251 +48
VI 738 1451 –40
Which of the above elements is likely to be : (d) the least reactive non-metal.

What is the significance of the terms — ‘isolated gaseous atom’ and ‘ground state’ while defining the ionization enthalpy and electron gain enthalpy?

What is the basic theme of organisation in the periodic table?

The size of isoelectronic species — $F^{-}$, $Ne$ and $Na^{+}$ is affected by

Which element do you think would have been named by (i) Lawrence Berkeley Laboratory

How do atomic radius vary in a period and in a group? How do you explain the variation?