Study notes on "MODERN PERIODIC TABLE"

MODERN PERIODIC TABLE

VALENCY

Valency may be defined as “the combining capacity of the atom of an element with atoms of other elements in order to acquire the stable configuration (i.e. 8 electron in valence shell. In some special cases it is 2 electrons).”

ATOMIC SIZE

It refers to the distance between the centre of nucleus of an isolated atom to its outermost shell containing electrons.

The atomic radius decreases on moving from left to right along a period. This is due to an increase in nuclear charge which tends to pull the electrons closer to the nucleus and reduces the size of the atom.

In a group atomic size increases from top to bottom due to increase in number of shells.

METALLIC AND NON-METALLIC PROPERTIES

In a period from left to right metallic nature decreases while non-metallic character increases.

In a group metallic character increases from top to bottom while non-metallic character decrease.