Question

how does atomic radii vary in a period??explain with eg??????

Answer 1

Atomic radius of the elements generally decreases from left to the right in a period because on moving from left to right in aperiod the nuclear charge gradually increases by one unit & one electron is also added in the electron shell.Due to this the electrons get attracted more & more towards the nucleus.consequently the atomic radii decreases .

Atomic radius of the elements increases as we move downwords in a group because on moving down a group there is an increase in principal quantum number & thus, increase in the number of electrons shells.Therefore the atomic size is expected to increase.