Question

How do atomic radii vary in a period and in a group? How do you explain the variation?

Answer 1

The elements that occur in nature are classified in the periodic table based on their atomic number. The elements in the atomic table are categorized into blocks that make them easier to correlate and thus make the comparison easier.

Complete step by step answer:
The elements in the periodic table are classified in the form of blocks, groups, and periods based on the properties that they show. The change in the group or the period indicates the change in the number of shells and the number of electrons in the shell.
While going along the period the number of electrons increases for the same number of shells so the effective nuclear charge increases in the elements and as a result the outermost electron will be more strongly attached to the central nucleus. This decreases the radius of the elements that go from left to right.
While talking of the group, an element goes to the next group when there is the addition of a new shell at the last of the orbitals. This increases the size of the element and thus the radius of the element is also increased as a result.

Note: According to Dalton’s theory, the atom is the most basic form of matter but the atom contains various subatomic particles like electrons and protons. The atomic structure of the atom depends on the electronic configuration in which the electrons are arranged inside the atoms. This electronic configuration is responsible for various properties that the atom shows.
The half-filled and full filled configuration of the orbitals are seen to be more stable than the rest of the configurations.