They are alike because some are made out of the same elements.
neutrons of all atoms are alike
They are all Elements and They are diiferent substances
the number of protons
The chemical elements in a group have similar properties.
Both are composed from chemical elements.
No, a compound is a substance composed of two or more different elements chemically combined in a fixed ratio. Each compound has a unique set of properties distinct from its constituent elements.
A null or empty set is a set that does not contain any elements.
'Mull Set' . I think you mean 'NULL SET'. This means a set with no elements, or an empty set.
its when too atoms are alike
All chemical elements are formed from protons, neutrons (excepting H-1) and electrons.
Compound are all alike because they all have two elements combined together like iron+sulfide=ironsulfide