Calculate the number of moles indicated in 180.0 g of Ca.(g – mol)

the old alchemists made significant contributions to science even though there starting premises were off a bit. their conclusions after failure would steer them into better directions for investigation. science is no more than close observation and the initial mistakes result in rethinking and retrying experiments.

radioactive decay occurs in unstable atomic nuclei – that is, ones that don't have enough binding energy to hold

the nucleus together due to an excess of either protons or neutrons.

oxygen, selenium, tellurium, and polonium.

they're all from the same group as sulfur (group 16).