The hardest mineral is while the softest is called

In the 1800s, one of the statements in john dalton's atomic theory was that atoms are indivisible. later experimental evidence led to the discovery of subatomic particles such as neutrons, electrons, and protons. what happened to the indivisible atom part of dalton's atomic theory, and why?

What material does not melt at any temperature

How many moles in .5g of sodium bromide?