Which general trend is observed in atomic radius as the elements in period 2 of the periodic table are considered from left to right?

• A. Atomic radius decreases
• B. Atomic radius first increases, then decreases
• C. Atomic radius remains constant
• D. Atomic radius increases

Answer: (A)

Verified step by step guidance

1. Understand that atomic radius refers to the size of an atom, typically measured as the distance from the nucleus to the outermost electron cloud.
2. Recall that in Period 2 of the periodic table, elements are arranged from left to right with increasing atomic number, meaning more protons and electrons are added sequentially.
3. Recognize that as you move from left to right across Period 2, the number of protons in the nucleus increases, which increases the positive charge attracting the electrons.
4. Note that although electrons are added as you move across the period, they are added to the same principal energy level, so the shielding effect does not increase significantly.
5. Conclude that the increased nuclear charge pulls the electron cloud closer to the nucleus, causing the atomic radius to decrease from left to right across Period 2.