Question

The characteristic of the last elements in the periods of a periodic table:
A.Orbital completely filled
B.Zero electron affinity
C.Zero tendency in accepting electrons
D.All of these

Answer 1

In a periodic table, the horizontal rows are known as periods and the vertical columns are called groups. The elements that lie at the end of the periods are the ones at the rightmost end of the table and are inert elements known as Noble gases.

Complete step by step answer:
The elements at the end of each period constitute the group $18$ elements known as the noble gases or inert gases. These gases are colourless, odourless and monoatomic as they are highly unreactive and are stable in an uncombined state.
There are six naturally occurring noble gases namely, Helium (He), Neon (Ne), Argon (Ar), Krypton (Kr), Xenon (Xe) and Radon (Rn). Their electronic configuration is as follows,
$He = 1{s^2}$
$Ne = 1{s^2}2{s^2}2{p^6}$
$Ar = [Ne]3{s^2}3{p^6}$
$Kr = [Ar]3{d^{10}}4{s^2}4{p^6}$
$Xe = [Kr]4{d^{10}}5{s^2}5{p^6}$
$Rn = [Xe]4{f^{14}}5{d^{10}}6{s^2}6{p^6}$
The valence shell in these elements is completely filled, which is the main reason behind them being unreactive.
As the valence shell of these elements are fully filled which makes them highly stable and they cannot accommodate any more electrons in their atomic orbitals as it will make the atom unstable. So, they have zero tendency to accept electrons and they exhibit zero electron affinity.

Hence option D is correct.

Note:
The modern periodic consists of $118$ elements arranged in the form of a table having $7$ periods and $18$ groups. These elements are arranged in the order of their increasing atomic numbers. Therefore, it can be said that the properties of elements are the periodic function of their atomic numbers.