Chapter 4, Problem 4.46QP

Interpretation Introduction

Interpretation: In third period of periodic table, the largest atom has to be identified.

Concept Introduction:

• Atomic radius is the distance between the centre of nucleus and the outermost shell of an atom.  According to Quantum mechanical model of an atom, there is no specific distance from nucleus after which an electron may not be found.  Hence, more specific definition is required for atomic radius.  This can be defined as metallic radius and covalent radius.
• Metallic radius is the half distance of two adjacent nuclei of identical metal atoms.
• Covalent radius is half distance of two adjacent nuclei, connected via a chemical bond.
• In a periodic table, the atomic radius varies across the period and down the group.  When moving down the group atomic radius increases as the electrons are added to a new shell.  When moving across the period, the electrons are added to the same subshell and hence the atomic radius decreases as there is less shielding and attraction between nucleus and valence electron increases.
• The more the atomic radius, the large the size of the atom will be and vice-versa.

To identify: The largest atom in third period of periodic table.