What properties of elements are called electronegativity? How the electronegativity of elements changes

What properties of elements are called electronegativity? How the electronegativity of elements changes:
a) in periods
b) in groups?

The property of the atoms of a given element to pull electrons away from the atoms of other elements in the compound is called electronegativity.
a) In the period from left to right, there is an increase in the electronegativity of the elements
b) In the main subgroups, the increase in the electronegativity of elements occurs from the bottom up.

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