CIE AS Chemistry (9701) exams from 2022

Revision Notes

1.3.2 Electronegativity Trends

Electronegativity: Trends

  • 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

Chemical Bonding Trends Down a Group, downloadable AS & A Level Chemistry revision notes

Electronegativity decreases going down the groups of the periodic table

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

Chemical Bonding Trends Across a Period, downloadable AS & A Level Chemistry revision notes

Electronegativity increases going across the periods of the Periodic Table

Trends down a group & across a period table

Chemical Bonding Table_3, downloadable AS & A Level Chemistry revision notes

Exam Tip

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.

Author: Francesca

Fran has taught A level Chemistry in the UK for over 10 years. As head of science, she used her passion for education to drive improvement for staff and students, supporting them to achieve their full potential. Fran has also co-written science textbooks and worked as an examiner for UK exam boards.

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