Nuclear decay
● What is nuclear decay?
○ There are three types of nuclear decay.
● What are the type of nuclear decay?
○ Alpha decay
During alpha decay, an alpha particle (essentially a helium nucleus with two
protons and two neutrons) is ejected. The alpha particle is relatively heavy
so it moves relatively slow (10% of the speed of light). Alpha decay only
occurs in atoms with a heavy nucleus, with a mass number greater than 100.
For example, the radioisotope uranium (with a mass number of 238, 92
protons and 146 neutrons), undergoes alpha decay.
When the uranium atom ejects an alpha particle, it loses two protons and
two neutrons, and the atom becomes a thorium atom (with a mass number
of 234, 90 protons and 144 neutrons).
○ Beta decay
During beta decay, a beta particle (similar to an electron), is ejected from the
nucleus of the atom. These particles are very small and negatively charged,
so they travel at around 90% the speed of light. When a nucleus undergoes
beta decay,a neutron is converted into a proton. This increases the atomic
number by one, but the mass number stays the same.
For example, when carbon (with a mass number of 14, 6 protons and 8
neutrons) undergoes beta decay, the atom becomes a stable nitrogen atom
● What is nuclear decay?
○ There are three types of nuclear decay.
● What are the type of nuclear decay?
○ Alpha decay
During alpha decay, an alpha particle (essentially a helium nucleus with two
protons and two neutrons) is ejected. The alpha particle is relatively heavy
so it moves relatively slow (10% of the speed of light). Alpha decay only
occurs in atoms with a heavy nucleus, with a mass number greater than 100.
For example, the radioisotope uranium (with a mass number of 238, 92
protons and 146 neutrons), undergoes alpha decay.
When the uranium atom ejects an alpha particle, it loses two protons and
two neutrons, and the atom becomes a thorium atom (with a mass number
of 234, 90 protons and 144 neutrons).
○ Beta decay
During beta decay, a beta particle (similar to an electron), is ejected from the
nucleus of the atom. These particles are very small and negatively charged,
so they travel at around 90% the speed of light. When a nucleus undergoes
beta decay,a neutron is converted into a proton. This increases the atomic
number by one, but the mass number stays the same.
For example, when carbon (with a mass number of 14, 6 protons and 8
neutrons) undergoes beta decay, the atom becomes a stable nitrogen atom
