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CHEM 121 Studioby Learn4Less · UBC CHEM 121

CHEM 121 glossary

Electronegativity

An atom's ability to attract the shared electrons of a bond toward itself (EN, χ\chi). On the Pauling scale it increases across a period and up a group, so F (3.98) is the most electronegative element.

Periodic trend: increases up and to the rightMain-group block of the periodic table shaded from light to dark. The property (electronegativity, ionization energy) increases across a period from left to right and up a group, so it is largest at the top right.increases across a period →increasesup a groupperiod 2period 6darker = larger (electronegativity, ionization energy)main groups only; noble gases aside

Electronegativity rises toward the top right (fluorine).

Example

Across period 2: Li 0.98, C 2.55, N 3.04, O 3.44, F 3.98. Down group 17: F 3.98, Cl 3.16, Br 2.96, I 2.66.

See alsoElectronegativity difference (ΔEN)Polar covalent bondPartial charge (δ+ / δ−)