Question

What is the trend in atomic radius from left to right on the periodic table?

Answer 1

Hint : We know that Atomic radius of any element is the distance between the nucleus of that element up to which the electron cloud is extended. The atomic radius is of the order ${{10}^{-10}}m.$ As a result, the valence electrons are held closer to the nucleus, and the atomic radius decreases.

Complete Step By Step Answer:
Periodic table consists of various trends related to atomic size, electronegativity, and electron affinity and ionization enthalpy of elements. These trends tend to change due to change in the structural properties of elements. In a periodic table, atomic radius has a decrease as we move from left to right in a period, while it has an increase while moving from top to bottom in a group.
While it has an increase while moving from top to bottom in a group. We know that the filling of electrons in an element takes place on different energy levels or shells called as K,L,M,N. As we move left to right in a period, addition of electrons in these shells called as K,L,M,N. shells takes place. While electrons along with protons get added up, the energy level in a particular period remains the same.
As you move from left to right, the nucleus gains protons. This increases the positive charge of the nucleus and its attractive force on the electrons. At the same time, electrons are added to the atoms as you move from left to right across a period. These electrons reside in the same energy shell and do not offer complete shielding. The effect of the increasing proton number is greater than that of the increasing electron number.

Note :
Remember that the fact that the energy levels along a period remain constant is of great importance as it affects the size of an atom. While the number of energy levels increases down the group results in the increase in the atomic size. They will exert an inward pull on the electron cloud which will shrink the size of the element. So, the size decreases from left to right in a period.