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Electronegativity down group 2

Learning outcomes

After studying this page, you should be able to:

  • describe and explain the trend in electronegativity down group 2

Electronegativity

The table shows electronegativity values for the common elements in group 2.

Element Symbol Atomic number Electronegativity
beryllium Be 4 1.57
magnesium Mg 12 1.31
calcium Ca 20 1.00
strontium Sr 38 0.95
barium Ba 56 0.89

Electronegativity is the ability of an atom to attract the bonding electrons in a covalent bond.

The table gives values on the Pauling scale which have no units. Fluorine (3.98) is the most electronegative element.

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Electronegativity in the periodic table

Description of trend

The graph shows how electronegativity varies down group 2:

  • as the atomic number increases, the electronegativity of the elements increases.
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Explanation of this trend

Going down group 2:

  • the atomic radius increases …
  • the outer electrons are more shielded from the attraction of the nucleus …
  • so electrons will be less strongly attracted to the nucleus.

You might expect electronegativity to increase going down the group because the nuclear charge increases. This does not happen, because the factors described above have a greater influence on the electronegativity.