Which of the following best describes the periodic trend for electronegativity across the periodic table?

• A. Electronegativity remains constant across periods and groups.
• B. Electronegativity increases from left to right across a period and decreases from top to bottom down a group.
• C. Electronegativity decreases from left to right across a period and decreases from top to bottom down a group.
• D. Electronegativity decreases from left to right across a period and increases from top to bottom down a group.

Answer: (B)

Verified step by step guidance

1. Understand that electronegativity is a measure of an atom's ability to attract and hold onto electrons in a chemical bond.
2. Recall the general periodic trend: as you move from left to right across a period (row) in the periodic table, the number of protons in the nucleus increases, which increases the effective nuclear charge experienced by the valence electrons, leading to a higher electronegativity.
3. Recognize that as you move down a group (column) in the periodic table, the atomic radius increases because additional electron shells are added, which causes the valence electrons to be farther from the nucleus and shielded by inner electrons, resulting in a decrease in electronegativity.
4. Combine these observations to conclude that electronegativity increases from left to right across a period and decreases from top to bottom down a group.
5. Use this understanding to evaluate the given options and identify the one that correctly describes this trend.