In the periodic table of elements, on moving from left to right across a period, the atomic radius A. Decreases B. Increases C. Remains unchanged D. Does not follow a definite pattern

The correct answer is A. Decreases.

As you move from left to right across a period in the periodic table, the atomic number increases. This means that the number of protons in the nucleus increases, and the number of electrons in the atom also increases. The increased number of protons in the nucleus creates a stronger pull on the electrons, which causes the atomic radius to decrease.

Option B is incorrect because the atomic radius decreases as you move from left to right across a period. Option C is incorrect because the atomic radius does decrease as you move from left to right across a period. Option D is incorrect because the atomic radius does follow