Question

25/35 electronegativity ______ from left to right within a period and ______ from top to bottom within a group. decreases, increases; stays the same, increases; increases, decreases; increases, increases

Explanation:

To solve this, we recall the trend of electronegativity in the periodic table. Electronegativity is the ability of an atom to attract electrons.

• Across a period (left to right): As we move from left to right in a period, the atomic number increases, and the effective nuclear charge increases while the atomic radius generally decreases. This makes atoms more capable of attracting electrons, so electronegativity increases.
• Down a group (top to bottom): As we move down a group, the number of electron shells increases, so the atomic radius increases. The outermost electrons are further from the nucleus, and the effective nuclear charge experienced by them is less. Thus, the ability to attract electrons (electronegativity) decreases.

So the correct pair is "increases, decreases".

Answer:

C. increases, decreases (assuming the third option is labeled C; if the original options had labels like A, B, C, D with the third being C, then the answer is C. increases, decreases)