Question

1. which of the following correctly describes the trend in atomic radius across period 2 from lithium (li) to fluorine (f)? atomic radius decreases because protons pull the electrons closer. atomic radius increases because electrons are added. atomic radius stays the same because shielding cancels the nuclear charge. atomic radius decreases because neutrons are added.

Explanation:

As you move across a period (from left - to - right, like from Lithium to Fluorine in Period 2), the number of protons in the nucleus increases. This leads to a greater nuclear charge. The electrons are added to the same energy level, so there is no significant increase in shielding. The increased nuclear charge pulls the electrons closer to the nucleus, causing the atomic radius to decrease.

Answer:

Atomic radius decreases because protons pull the electrons closer.