Which Force Actually Moved

You'll learnwhy atoms shrink across a row and grow down a column, from nuclear charge and distance.

Everyone memorises the two arrows on the periodic table, and everyone flips them under pressure. Both of them come out of one tug-of-war: the nucleus pulling the outer electrons in, and distance and shielding holding them out. Twelve short steps; press Next for each one.

12 STEPS · 6 QUICK CHECKS · RADIUS IN PM · IONIZATION ENERGY IN KJ/MOL · v3

the pull in · the distance out · which one changed

Before you start

What you're looking at

The two trend arrows on a periodic map, then the single atom they both come from.

The question

Two forces act on an outer electron. Which one actually changes as you move?

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