EVERYDAY SCIENCE

Detailed explanation-1: -Down a group, the number of energy levels (n) increases, so there is a greater distance between the nucleus and the outermost orbital. This results in a larger atomic radius. Ionic radius is the distance from the nucleus to the outer edge of the electron cloud of an ion.

Detailed explanation-2: -In a period all elements have same number of shells. As we move from left to right in a period, the number of electrons goes on increasing.

Detailed explanation-3: -The number of electrons in the outermost shell of a particular atom determines its reactivity, or tendency to form chemical bonds with other atoms. This outermost shell is known as the valence shell, and the electrons found in it are called valence electrons.

Detailed explanation-4: -Going across a period (from left to right), the number of protons increases and therefore the nuclear charge increases. (Going across a period, the number of electron energy levels remains the same but the number of electrons increases within these energy levels.

Detailed explanation-5: -On the periodic table, atomic radius generally decreases as you move from left to right across a period (due to increasing nuclear charge) and increases as you move down a group (due to the increasing number of electron shells).