PROPERTIESPROPERTIESOFOF

RADIO-RADIO-ISOTOPESISOTOPES

by:- Aman Verma

Emits Radiation

● Radioactive isotopes are unstable so they go into a radioactive decay emitting radiations.

● Till they become stable● 3 types of radiations:

Alpha particles (α)

Beta particles (β)

Gamma particles (γ)

Radiation

Half-life (t1/2)

● The time taken for the activity of a radioisotope to reach half of it's original value.

● Thus activity decreases with time.

Half-life (t1/2)

For example, suppose we had 20,000 atoms of a radioactive substance. If the half-life is 1 hour, how many atoms of that substance would be left after:

Time(after)

Number of atoms remaining

% of atoms remaining

1 Hour (one lifetime)

10,000 50%

2 hours (Two lifetimes)

5,000 25%

3 hours (Three lifetimes)

2,500 12.5%

Half-life & Radioactivity

Penetration Property

● Radioactive radiations have different PENETRATING ability.

● Depends on ''thickness and density'' of material

Penetrating Power of Radiation

n

Skin & paper

5mm brass 6mm Al

Pb & concrete

Very thick concrete (2m)

α = alpha β = Beta γ = Gamma n = Neutron

Same Chemical properties

● Isotopes of same element have same Chemical properties.

● Due to same no. of electrons in the 'Outermost Shell'.

Different Physical properties

● Differ from isotopes to isotopes.

● Based on number of neutron.

Different Physical properties

● Differ from isotopes to isotopes.

● Based on number of neutron.