How do we determine the atomic mass of an element with its isotopes?

What is atomic mass of an element?

Can we know the atomic radius of an element ?

How do you determine the atomic mass of an unknown metal if you know its density and dimension of its unit cell ? Explain .

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Atomic mass of the element Sulphur-

How do we get fits?

DO the atom of an element and its ion have same size ?

How do we obtain synthetic fibres?

DO the atom of an element and its ion have same value ?

How do we get a rainbow ?