- Electronegativity varies across Periods and down the Groups of the Periodic Table
Down a group
- There is a decrease in electronegativity going down the Group
- The nuclear charge increases as more protons are being added to the nucleus
- However, each element has an extra filled electron shell, which increases shielding
- The addition of the extra shells increases the distance between the nucleus and the outer electrons resulting in larger atomic radii
- Overall, there is decrease in attraction between the nucleus and outer bonding electrons
Across a period
- Electronegativity increases across a Period
- The nuclear charge increases with the addition of protons to the nucleus
- Shielding remains reasonably the same across the Period as no new shells are being added to the atoms
- The nucleus has an increasingly strong attraction for the bonding pair of electrons of atoms across the Period of the Periodic Table
- This results in smaller atomic radii
Remember the general trend is an increase in electronegativity towards the top right of the Periodic Table.
Fluorine is the most electronegative element in the periodic table.