Question

How do electronegativity values change across a row of representative elements?

Answer 1

As we face the Periodic Table, from LEFT to RIGHT....

Explanation:

`"Electronegativity"` INCREASES across a Period, and DECREASES down a Group.

Why? Well `"electronegativity"` is conceived to be ability of an atom involved in a chemical bond to polarize electron density towards itself. It is intuitively reasonable that for elements of a GIVEN Period, a given row of the Periodic Table, that electronegativity INCREASES across the Period, given that the nuclear charge, i.e. `Z_"the atomic number"` INCREASES across the Period. And in fact fluorine, `Z=19`, is the most electronegative element.

On the other hand, we know that electronegativity DECREASES down a Group of the Periodic Table...and again this is reasonable, given that as we descend a column of the Periodic Table we remove the valence shell of ELECTRONS from the positively-charged nuclear core, and thus electronegativity DECREASES...

And so as physical scientists, as chemists, we should look at some actual data....

I hope you can see the numbers...because I cannot...