Question

X,Y,Z are the elements of Dobereiner's triad. If the atomic mass of X is 7 and that of Z is 39, what should be the atomic mass of Y.

Answer 1

Mass of Y will be the mean mass of X & Z
So mass of Y =
$\frac{7 + 39}{2 }$
Y = 23u

Answer 2

Answer: The correct answer is 23 u

Explanation:  All the bodies on earth are made up of small particles called atoms and they are made up of electrons, protons, and neutrons where electrons carry the negative charge, protons carry the positive charge and neutrons carry the neutral charge and they also contain the atomic number and atomic masses where atomic mass is the quantity of matter contained in an atom of an element. It is expressed as a multiple of one-twelfth the mass of the carbon-12 atom, 1.992646547 × 10−23 gram, which is assigned an atomic mass of 12 units or it can also be considered as the mass of the atom in any particular chemical substance given or provided.

Given that = the atomic mass of X is 7

           = atomic mass of Z is 39

Solution

Mass of Y will be the mean mass of X & Z

So mass of Y =

7 + 39 / 2

Y = 23u

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