Question

an atom of an element B has mass number 40 and 15 protons. Write the electron arrangement of the atom​

Answer 1

ANSWER

Z

A

X, where A stands for the atomic mass number which is the sum of protons and neutrons in the atom of an element and Z stands for an atomic number of the element which is the number of electrons in an atom of an element.

Atomic mass = Number of electrons + Number of neutrons

Atomic number = Number of protons = Number of electrons

Therefore, atomic mass =15+16=31 and atomic number is =15.

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