What trend is observed in electronegativity as you move across a period from left to right?

As you move across a period from left to right in the periodic table, electronegativity increases. This trend occurs because, as you go across a period, the number of protons in the nucleus increases while the electron shielding effect remains relatively constant. As a result, the increased positive charge in the nucleus attracts the bonding electrons more strongly. Consequently, elements on the right side of the periodic table, such as fluorine or oxygen, tend to have a higher electronegativity compared to those on the left side, such as lithium or sodium. This increase in electronegativity is a fundamental concept in understanding chemical bonding and the behavior of elements in reactions.