Which of the following changes is observed when we move across the row from left to right in the periodic table? atomic radius increases atomic radius decreases number of protons decreases chemical reactivity of metals increases

Answer : The correct option is, Atomic radius decreases.

Explanation :

Atomic radius of an atom is defined as the total distance from the nucleus to the valence shell of the atom.

As moving from left to right in a period, more electrons are added in the same shell and the attraction between the last electron and nucleus increases, which results in the shrinkage of size of an atom.

Thus, decreasing the atomic radii of the atom on moving towards right of the periodic table.

As we are moving from left to right in a period, the number of protons increases due to increase in the atomic number of an atom.

Chemical reactivity : It is defined as the tendency of an element to loose or gain electrons.

Metals are the elements which loose electrons and hence, their chemical reactivity will be the tendency to loose electrons.

Their chemical reactivity decreases as we move from left to right in a period because the valence shell come closer to nucleus as we move from left to right. So, tendency to loose electrons becomes difficult due to greater attraction between nucleus and valence electron.

Hence, the correct option is, Atomic radius decreases.