Question

when moving from left to right across a period,the outer electrons feel a ____ attraction towards the nucleus and the atomic radius ____.

a stronger, decreases

b stronger, increases

c weaker, increases

d weaker, decreases

Explanation:

To solve this, we recall the periodic trends: As we move left to right across a period, the atomic number (and thus proton number) increases. This increases the nuclear charge. The outer electrons are in the same energy level (so shielding from inner electrons doesn't increase much), so the attraction between outer electrons and the nucleus becomes stronger. A stronger nuclear attraction pulls the outer electrons closer, so the atomic radius decreases.

Answer:

a. Stronger, decreases