Nuclear Equations 

Nuclear equations are used to represent radioactive decay by using the ELEMENT SYMBOLS.

They’re written in the following way:

The SYMBOLS for the radiation types are written in the following way:

Let’s look at some examples:

Alpha Decay

During ALPHA decay a HELIUM NUCLEUS (2 protons and 2 neutrons) is given off.

This causes the MASS NUMBER to decrease by 4 and the ATOMIC NUMBER to decrease by 2.

This means the CHARGE of the nucleus decreases by 2.

During alpha decay, the number of PROTONS in a nucleus changes, so the ELEMENT changes.

E.g. Let’s say we have a Radon-219 nucleus undergoing ALPHA DECAY to form a polonium nucleus:

In this example, we know the mass number (219) and atomic number (86) of RADON, but we need to work out the mass and atomic number of POLONIUM:

Beta Decay

For BETA decay, an ELECTRON is given off and a NEUTRON is turned into a PROTON.

This causes the MASS NUMBER to STAY THE SAME, and the ATOMIC NUMBER to increase by 1.

This means the CHARGE of the nucleus INCREASES by 1.

During beta decay, the number of PROTONS in a nucleus changes, so the ELEMENT changes.

E.g. A carbon-14 nucleus undergoing beta decay to form nitrogen.

Gamma Decay

GAMMA decay only gives off an ELECTROMAGNETIC WAVE with ENERGY but NO MASS (neutrons or protons).

This causes the MASS and ATOMIC number to STAY THE SAME.

The CHARGE of the nucleus also STAYS THE SAME.

As the number of protons does NOT change, the ELEMENT STAYS THE SAME during gamma decay.

E.g. A uranium-238 nucleus emitting GAMMA radation.