About That One Little Electron . . .

A number of readers have objected to a statement in last week’s Mind Over Matter column suggesting that one electron is responsible for the difference in chemical reactivity between neon and sodium. Times science writer K.C. Cole responds:

“Strictly speaking, readers who objected to my statement that one little electron makes the difference between highly reactive sodium and inert neon were correct: Sodium also has an extra proton. But protons do not affect chemical properties. The fact that neon is sedate and sodium a reactive metal is entirely due to the shell structure of their outer electrons; in that context, it’s the one extra electron that makes all the difference. Of course, I was comparing neutral atoms, not ions.”

--Compiled by Times medical writer Thomas H. Maugh II