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