Question

1. graph atomic radius vs. atomic number for the period 3 elements. what trend do you observe? why?

Explanation:

Step1: Analyze the graph trend

As atomic number increases (from left to right in the graph), the atomic radius decreases.

Step2: Explain the reason

In Period 3, as atomic number increases, the number of protons in the nucleus increases. The electrons are added to the same shell. The increased positive charge in the nucleus (due to more protons) pulls the electrons in the shell closer, resulting in a decrease in atomic radius.

Answer:

The trend is that as atomic number increases, atomic radius decreases. This is because with more protons (higher atomic number) in the same - shell period (Period 3), the nuclear charge increases, pulling electrons closer.