Trend

Three Important Periodic Trends Definition of Periodic Trend: The tendency of a certain characteristic of an element to increase or decrease as they progresses along a period or group on the periodic table of elements Definition of Term Atomic Radius - One half the distance between the nuclei of identical atoms that are bonded together. Picometers (pm) Ionization Energy - The energy required to remove 1 electron from a neutral atom of an element. kiloJoules per Mole (kJ/mol) Electronegativity - The measure of the ability of an atom in a chemical compound to attract the electrons of another atom in the compound. Trend Across the PT The atomic radii decreases as you move across each period, as you add more protons to help pull the electrons closer to the nucleus.