Helium atom has an atomic mass of 4 u and two protons in... - Science

Question

Helium atom has an atomic mass of 4 u and two protons in its nucleus. How many neutrons does it have?

Answer

Number of neutrons = Atomic mass - Number of protons

$= 4 - 2 = \mathbf{2}$

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On the basis of Thomson's model of an atom, explain how the atom is neutral as a whole.

On the basis of Rutherford's model of an atom, which sub-atomic particle is present in the nucleus of an atom?

Draw a sketch of Bohr's model of an atom with three shells.

4. What do you think would be the observation if the $\alpha$ -particle scattering experiment is carried out using a foil of a metal other than gold?

Name the three sub-atomic particles of an atom.

Write the distribution of electrons in carbon and sodium atoms.

If K and L shells of an atom are full, then what would be the total number of electrons in the atom?

How will you find the valency of chlorine, sulphur and magnesium?

Subject: Science
Class: class 9
Chapter 4: Structure of the Atom
Medium: English Medium