Question

The number of electrons, neutrons, and protons on a species is equal to 10, 8, and 8 respectively. The proper symbol of the species is:
A.${}_{\text{8}}^{{\text{16}}}{\text{O}}$
B.${}_{\text{8}}^{{\text{18}}}{\text{O}}$
C.${}_{{\text{10}}}^{{\text{18}}}{\text{Ne}}$
D.${}_{\text{8}}^{{\text{16}}}{{\text{O}}^{{\text{2 - }}}}$

Answer 1

Many scientists had tried to describe the structure of an atom for many years. But the widely accepted one is that of Bohr’s atomic model. Bohr had described that the atom consists of a nucleus and the electrons revolving around the nucleus. The nucleus consists of positively charged protons and neutral entities neutrons.

Complete step by step answer:
Following steps can be used to calculate the atomic number and atomic mass of a species if we are provided with the number of electrons, protons, and neutrons:
Atomic mass or mass number of a species is equal to the sum of the number of protons and neutrons.
Therefore, for the given species the atomic mass is equal = 8+8 = 16.
The atomic number of a species is equal to the number of protons of that species. Hence, the atomic number of given species is 8.
The species with atomic number 8 is Oxygen.
The number of electrons present on the species is 10 that means two more than the number of protons. This means that there is a negative charge of 2 on the atom because of 2 excess electrons.
Since we have calculated the atomic number, mass number, charge on the atom, and predicted the element and hence its symbol, now we have to learn the rules of symbol writing:
The atomic number of the element is always written on the bottom left of the symbol.
The mass number is written on the top left,
And the charge is always written on the top right.
Thus, we can write the symbol of the given species as: ${}_{\text{8}}^{{\text{16}}}{{\text{O}}^{{\text{2 - }}}}$
This means that option D is the correct answer.

Note: Please note that atoms are composed of negatively charged particles called electrons, positively charged particles known as protons, and the neutral ones called a neutron.
Electrons were first discovered by J.J. Thomson in 1891.
Protons were discovered by Ernest Rutherford in 1920.
And the discovery of neutrons was done by Chadwick in 1932.