Question

Moving across a ______ of the periodic table, the elements show an increase in ______ character. (Group/Period, metallic/non-metallic

• A. Period
• B. non-metallic

Answer 1

• Modern periodic table is the arrangement of elements on the basis of increasing atomic number in 7 horizontal rows and 18 vertical columns. Horizontal rows are termed as Periods while the vertical columns are termed as Groups.
• Non-metallic character is the ability of an atom to gain either one or more electrons to obtain a stable electronic configuration. For example, Sulfur (S) gains two electrons (e^-) to form a Sulfur ion (S^2-).

$\mathrm{S}\left(\mathrm{s}\right)+2{\mathrm{e}}^{-}\to {\mathrm{S}}^{2-}\left(\mathrm{aq}\right)$

• In a Period, the effective nuclear charge increases on moving from left to right due to the successive increase in the atomic number.
• Due to the increase in the nuclear charge, it becomes easier for the atoms to gain electrons.
• It can be concluded that on going from left to right across a Period, the tendency of an atom to gain electrons increases, and therefore, the non-metallic character increases across a Period. Hence, Moving across a Period of the periodic table, the elements show an increase in non-metallic character.