The tendency of an atom to attract electrons towards itself is called

Electronegativity

Explanation:

Element: An element is a substance which can not be split into simpler units by an ordinary chemical process

Electronegativity: This is the power of an atom in a molecule to attract electrons. The electronegativity of an element increase across the period in the periodic table and decreases down the group. The most electronegative elements are the reactive non metals.

Examples of electronnegative element include, Oxygen, Chlorine, Fluorine, Nitrogen, sulphur etc.