What electronegativiy increases from left to right and from top to bottom on the periodic table?

Electronegativity typically increases from left to right across a period on the Periodic Table due to increasing nuclear charge, which attracts electrons more strongly. Conversely, it decreases from top to bottom within a group because the addition of electron shells reduces the effective nuclear charge felt by the outermost electrons, making it harder for atoms to attract additional electrons. This trend is influenced by both atomic size and the effective nuclear charge.