Electronegativity is a measure of how easy it is for an atom to attract another electron. the elements he, ne, and ar have the lowest electronegativity values. what do these elements have in common?

These atoms and other atoms in group 8A have constant valence shell.it means that all of them have 8 electrons in their valence shell (except helium that has only 2 electrons )and they don't want to attract electrons.
that s why they don't have electronegativity.
hope this helps

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