Early Atomic Models

In an atom, neutrons are present in the nucleus. 

In an atom ${}_{\text{13}}{\text{AI}}^{\text{27}}$, find the number of neutrons.

In an atom ${}_{\text{13}}{\text{AI}}^{\text{27}}$, find the number of protons.

In an atom ${}_{\text{13}}{\text{AI}}^{\text{27}}$, find the number of electrons.

The gravitational force between a $\mathrm{H}$-atom and another particle of mass $m$ will be given by Newton's law $F=G\frac{M\cdot m}{r^2}$, where $r$ is in metre and

In an atom, electrons are present in the nucleus. 

In an atom the number of _____ is equal to the number of electrons that revolve around the nucleus

In an atom the number of _____ is equal to the number of electrons that revolve around the nucleus

Describe the atomic model of helium atom.

Describe the atomic model of hydrogen atom.

_____ is the lightest element.

In an atom, electrons are present in the nucleus. 

$\alpha$ - particle consists of

Rutherford deduced that Thomson ‘plum pudding’ model of the atom was certainly correct.

A standing wave in a string 35 cm long has a total of six nodes including those at the ends. Hence, wavelength of the standing wave is

Cotyledons are also called-

Which of the following properties of atom could be explained correctly by the Thomson Model of atom?

The modern periodic table given by

In the experiment for the determination of $\frac{e}{m}$ of electrons by the Thomson method, electric and magnetic fields are

In Thomson's mass spectrographs, when an electric field of $2\times {10}^4 \mathrm{V} {\mathrm{m}}^{-1}$ is applied then the deflection produced on the screen is $20 \mathrm{mm}$. If the length of the plates is $5 \mathrm{cm}$ and the distance of the screen from plates is $21 \mathrm{cm}$ and the velocity of positive ions is ${10}^6 \mathrm{m} {\mathrm{s}}^{-1}$, then their specific charge will be: