Physical properties of periodic table:-

What is Atomic Size?

Atomic size is the distance between the centre of the nucleus of an atom and its outermost shell.

What is Atomic Radius?

An atomic radius is defined as the “shortest distance between the atom’s nuclei and the outermost shell of the atom. “

In general, the atomic radius decreases as we move from left to right in a period and it increases when we go down a group. This is because in periods the valence electrons are in the same outermost shell. The atomic number increases within the same period while moving from left to right which in turn increases the effective nuclear charge. The increase in attractive forces reduces the atomic radius of elements.

Covalent radius:-

Covalent radius is one half the distance between the nuclei of two covalently bonded atoms of the same element in a molecule.

Ionic radius:-

The ionic radius is half the distance between atomic ions in a crystal lattice.

Metallic radius:-

The metallic radius is the radius of an atom joined by metallic bond. The metallic radius is half of the total distance between the nuclei of two adjacent atoms in a metallic cluster.

Ionization potential:-

The amount of energy required to remove an electron from the outermost shell of an isolated neutral gaseous atom or molecule.

The ionization energy is a measure of the capability of an element to enter into chemical reactions requiring ion formation or donation of electrons. It is also generally related to the nature of the chemical bonding in the compounds formed by the elements.

Generally, the Ionization potential increases from left to right along a period. The reason for this can be that along a period, the atomic size decreases and the valence shell is closer to the nucleus. Thus more energy is required to remove an electron from the valence shell.

As we move down the group, ionization energy decreases because while moving down the group atomic size increases due to this fact the force of attraction between the nucleus and the valence electrons is weaker. So, it becomes easy to remove an electron from an atom. Thus, the ionization decreases down the group.

PRESENTED BY

Banalaxmi pujhari( Lect. in chemistry)