How do electronegativity values generally change as you move down a group and across a period in the periodic table?

• A. Electronegativity decreases both down a group and across a period from left to right.
• B. Electronegativity increases down a group and decreases across a period from left to right.
• C. Electronegativity increases both down a group and across a period from left to right.
• D. Electronegativity decreases down a group and increases across a period from left to right.

Answer: (D)

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. Recognize that as you move down a group in the periodic table, atoms have more electron shells, which increases the distance between the nucleus and the valence electrons, reducing the nucleus's pull on bonding electrons. Therefore, electronegativity decreases down a group.
3. Know that as you move across a period from left to right, atoms have more protons in the nucleus (increased nuclear charge) but the same number of electron shells, which increases the effective nuclear charge experienced by valence electrons, making atoms more electronegative.
4. Combine these trends to conclude that electronegativity decreases down a group and increases across a period from left to right.
5. Use this understanding to evaluate the given answer choices and identify the correct trend for electronegativity in the periodic table.