Question

Describe the experiment by which rutherford discovered the presence of then nucleus in an atom.​

Answer 1

Rutherford's experiment of an atom

• Ernest Rutherford was interested in knowing how the electrons are arranged within an atom
• Rutherford designed an experiment for this in this experiment fast-moving Alpha particles are made to fall on a thin gold foil .

What is done in this experiment ;

• he selected a gold foil because he wanted as thin as layer as possible this gold foil was about 1000 atoms thick .
• Alpha particle are double recharge Helium ion . since they have mass of 4u the first moving Alpha particles have a considerable amount of energy
• it was expected that Alpha particles would be deflected by the subatomic particle in the gold atoms . what is the Alpha particle where much heavier than the protons he did not expect to see large deflection .

Scattering of a-particles by a gold foil diagram in attachment !

Result of the experiment

• most of the fast-moving Alpha particles passed through the gold foil
• some of the Alpha particles where deflected by the fall by small angles
• surprisingly one out of every 12000 particles appeared to rebound .

Answer 2

Rutherford's alpha (α) particle scattering experiment resulted in discovery of nucleus in atom.

Rutherford concluded from the α-particle scattering experiment that:-

• Most of the space inside the atom is empty because most of the α-particles passed through the gold foil without getting deflected.

• Very few particles were deflected from their path, indicating that the positive charge of the atom occupies very little space.

• A very small fraction of α-particles were deflected by very large angles, indicating that all the positive charge and mass of the gold atom were concentrated in a very small volume within the atom.

》On the basis of his experiment,

Rutherford put forward the nuclear model of an atom, which had the following features:-

• There is a positively charged center in an atom called the nucleus. Nearly all the mass of an atom resides in the nucleus.

• The electrons revolve around the nucleus in well-defined orbits.

• The size of the nucleus is very small as compared to the size of the atom. Rutherford's alpha particle scattering experiment shows the presence of nucleus in the atom.

✅ It also gives the following important information about the nucleus of an atom:-

• The nucleus of an atom is positively charged.

• The nucleus of an atom is very dense and hard.

• The nucleus of an atom is very small as compared to the size of the atom as a whole.

Rutherford model of the atom is also called Nuclear model of the atom.

Hope it is helpful to you mate.......