Atomic Models

What is an atomic model? 

A certain negative ion ${\mathrm{X}}^{-2}$ has in its nucleus $18$ neutrons and $18$ electrons in its extra nuclear structure. What is the mass number of the most abundant isotope of '$\mathrm{X}$' :

Calculate the number of atoms, ${\mathrm{e}}^{-}, {\mathrm{p}}^{+}, {\mathrm{n}}^0$ and nucleons in $10$ molecules of ${\mathrm{Al}}_2({\mathrm{SO}}_4{)}_3$.

Calculate the number of atoms, ${\mathrm{e}}^{-}, {\mathrm{p}}^{+}, {\mathrm{n}}^0$ and nucleons in $2$ million molecules of ${\mathrm{NaHCO}}_3$.

Calculate the number of atoms, ${\mathrm{e}}^{-}, {\mathrm{p}}^{+}, {\mathrm{n}}^0$ and nucleons in two hundred molecules of ${\mathrm{KClO}}_3$.

Calculate the number of atoms, ${\mathrm{e}}^{-}, {\mathrm{p}}^{+}, {\mathrm{n}}^0$ and nucleons in $5$ molecules of ${\mathrm{H}}_3{\mathrm{PO}}_3$.

Number of electrons in 10 molecules of ${\mathrm{CaCO}}_3$.

Calculate number at neutrons present in $12\times {10}^{23}$ atoms of oxygen $\left({}_8{}^{17}\mathrm{O}\right)$

What is the atomic number of $\mathrm{Na}$?

Why electrons don't neutralise in an atom?

How many electrons are there in a molecule of ${\mathrm{HClO}}_4$?

Calculate the radius of ${}^{70}\mathrm{Ge}$.

List the limitations of Thomson's atomic model.

What is the need of atomic models?

Which of the following element has the maximum density of nucleus?

In a radioactive decay ${{}_{90}\mathrm{Th}}^{232}$ is transformer into ${{}_{82} \mathrm{Pb}}^{208}$ calculate number of beta particles emitted.

State the failures of Thomson's atomic model.

Isobars have

The number of protons, electrons and neutrons respectively in the element ${}_{93}{}^{237}\mathrm{Y}$ are

Atomic number and mass number of an element $\mathrm{M}$ are $25$ and $52$ respectively. The number of electrons, protons and neutrons in ${\mathrm{M}}^{2+}$ ion are respectively