Electronegativity

Electronegativity is a measure of how strongly an atom attracts extra electrons to itself. Electronegativity is assigned a number on an arbitrary scale from roughly 0 to 4, depending on the method of calculation. Metals have electronegativities less than 2. Electronegativity increases from left to right on the periodic chart, and decreases from top to bottom. Thus fluorine is the most electronegative atom, having an electronegativity very close to 4.