Barrons SAT Subject Test Chemistry, 13th Edition

Notes: The atomic radius is usually given for metal atoms, which are shown in
gray, and the covalent radius is usually given for atoms of nonmetals, which
are shown in black.

Notice in Table 5 that the electronegativity decreases down a group and
increases across a period. The inert gases can be ignored. The lower the
electronegativity number, the more electropositive an element is said to be. The
most electronegative element is in the upper right corner—F, fluorine. The most
electropositive is in the lower left corner of the chart—Fr, francium.

TIP

The most electronegative element is F, in the upper right corner.

Table 5. First Ionization Energies and Electronegativities

TIP

The least electronegative element is Fr, in the lower left corner.