Physics 2000 Science Trek The Periodic Table

Periodic Properties the elements in the table are arranged in order from lightest to heaviest, and elements in the same column have matching properties. That's right.

That means that elements whose atomic weights are really close together can be very different, and some elements with far-apart atomic weights are very similar. As you move from lighter atoms to heavier ones, you keep periodically running across the same properties...

Hence the name periodic table. Oh, right.

I don't mean to pick on you; what you said was actually a very important insight. The periodic table is full of repeating patterns. Take atomic size, for instance: atoms get bigger as you move down a column, and smaller as you move to the right across a row, or period.

That's so weird! I'd think the atoms would just get bigger as they got heavier; why do they get smaller as you move to the right?

The answer lies in the underlying structure of those atoms...