Question

so....
I have doubt in Chemistry

now lemme explain the scenario...

Neutron was discovered by Sir James Chadwick in 1920..
then, how Mendeleev calculated the mass of Beryllium in 1869??

As u know we need proton and neutron for calculation of atomic mass.​

Answer 1

Answer:

Mendeleev was wrong and it was proved

Answer 2

Answer:

For calculating atomic mass there is no need to know the number of neutrons and protons as it is calculated using some specific components.

But to calculate the mass number of an atom , we need to add the number of neutrons and protons present in the nucleus of that atom.

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Hope it helps you ☆○☆○☆