Atomic models were developed through indirect observation even though no one had seen an atom. There were many experiments of which I know nothing about, but in the end the scientists managed to come up with a formula and various models to describe atoms.
Mass / volume = density
30.943g / 35ml = 0.88408571g/ml
Answer:
An Element is a substance made up of only one type of atom as like gold, copper, oxygen, etc.
Copper sulphate with molecular formula 
, the elements are copper, sulphur and oxygen. It is formed by combination of 
cation and 
anion.
Copper sulphide with molecular formula 
, the elements are copper and sulphur. It is formed by combination of cation and 
anion.
