Use the information below to explain why the atomic radius decreases across a period.

Detail is given below.

Explanation:

Atomic radius  trend along period:

As we move from left to right across the periodic table the number of valance electrons increases. The atomic size tend to decrease in same period of periodic table because the electrons are added with in the same shell. When the electron are added, at the same time protons are also added in the nucleus. The positive charge is going to increase and this charge is greater in effect than the charge of electrons. This effect lead to the greater nuclear attraction. The electrons are pull towards the nucleus and valance shell get closer to the nucleus. As a result of this greater nuclear attraction atomic radius decreases and ionization energy increases because it is very difficult to remove the electron from atom and more energy is required.

we can see in picture A there is one positive charge and force of attraction is 2.30×10⁻⁸ N

In picture D there are 2 positive charge and force of attraction is 4.60×10⁻⁸ N

So by increasing the positive charge force of attraction also increases.

In F we can see there is more positive charge thus force of attraction is also greater.