Question

Arrange the following elements in order of increasing metallic character: Ra, Sn, In, S, Ba, As. Rank elements from least to most metallic character.

Answer 1

Metallic character of an atoms is the ability of lose electron and form cations. An atom that can readily lose an electron and form cation is have more metallic character.

Factors depending upon metallic character

1) atomic radius - larger the atomic radius higher the metallic character. If larger the atomic radius the valence electron have less attractive force by the nucleus. So that can readily lose. If atomic radius is small ate valence electron is strongly attracted by nucleus .so it can't lose the electron.

Atomic radius gradually decreases from left to right across a periodic table. This is because, within a period of elements, all electrons are added to the same shell. However, at the same time, protons are being added to the nucleus,so nuclear charge increases.there is a greater nuclear attraction. That is pulling the atom's shell closer to the nucleus. So the valence electrons are held closer towards the nucleus of the atom. As a result, the atomic radius decreases.

Down a group, atomic radius increases. The valence electrons occupy higher levels due to the increasing principle quantum number (n). As a result, the valence electrons are further away from the nucleus as ‘n’ increases. Electron shielding effect prevents these outer electrons from being attracted to the nucleus; so valence electron are loosely held, and the resulting atomic radius is large.

Increasing order of atomic radius

S<As< Sn<In< Ba< Ra

If atomic radius increases mettalic character increases so increasing order of mettalic character

S<As< Sn<In< Ba< Ra