Final answer:
Electronegativity increases from left to right across a period due to decreasing atomic size and increases in nuclear charge, which makes the nucleus more effective in attracting bonding electrons. So the correct option is B
Step-by-step explanation:
The statement that describes a periodic trend of electronegativity is: Electronegativity increases from left to right across a period. This trend occurs because as you move from left to right across a period, the atomic size decreases, so the nucleus can more effectively attract bonding electrons. Conversely, electronegativity generally decreases from top to bottom within a group due to the increase in atomic size making the nucleus less effective at attracting bonding electrons. Alkali metals at the left end of a period have the lowest electronegativities, while halogens near the right end have the highest, with noble gases not typically forming compounds and thus not usually assigned electronegativity values.