How did dmitri mendeleev organize the periodic table

According with atomic weight and valences

Explanation:

Mendeleev organized the periodic table according atomic weight because the elements exhibit an apparent periodicity of properties, and the magnitude of the weight determines the character of the element

explanation:

let the different atoms be x and y. each with four protons and same mass will be represented as follows.

mass number is number of protons + number of neutrons.

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since, it is given that one has a negative charge while the other is neutral. therefore, there will be increase in number of protons and the atom will be represented as follows.

according to periodic table, mass number of beryllium is 9 and it has atomic number 4 so, the atoms will be and .  

the protons and neutrons will be located inside the nucleus whereas the electrons will be revolving around the nucleus.  

i'm wiling to try and you : )