The  alpha, α – particles possess following 10 properties:

1.     Alpha, α – particle carries double the positive charge of proton, which is equal to the charge on the helium nucleus.

2.      Mass of an alpha, α – particle is roughly four times that of hydrogen atom i.e. it is equal to the mass of the helium nucleus.

The above two properties establish that an alpha, α – particle is equivalent to helium nucleus (or a helium atom which has lost its two orbital electrons i.e. a doubly ionized helium atom).

3.      Alpha, α – particles are deflected by electric and magnetic fields.

4.       The velocity of alpha, α – particle ranges between 1.4 x 10⁷ ms^-1 to 2.1 x 10⁷ ms^-1 , depending upon the source emitting it.

5.      Because of large mass, the penetrating power of  α – particle is very small, it being 1/100 times that due to beta, β – rays and 1/10,000 times that due to γ – rays . α – particle can be easily stopped by an aluminium sheet, only 0.02 mm thick.

6.      Because of large mass and large velocity, α – particle have large ionizing power. Each α – particle produces thousands of ions before being absorbed.

7.      The range of alpha, α – particles in air (distance through which they can travel in air) depends upon the radioactive source producing it. At normal pressure in air, the range of α – particle varies from 3 to 8 cm.

8.      Alpha, α – particles produces fluorescence in certain substances, like barium – plantinocyanide and zinc-sulphide.

9.      Alpha, α – particles affected photographic plate slightly.

10.  Alpha, α – particles are scattered while passing through thin metal foils. Most of the α – particles are scattered at small angles, but a few of them are scattered at an angle more than 90⁰ also.

These are the 10 properties of  α – particles, if you know more, please discuss.

Brain Teaser:

Please answer the following question:

The penetrating power of  α – particles is:

1. less than beta particles

2, less than gamma particles

3. both a) and b)

4. none of the above,

Please submit your answer in comment section.