What is an atomic number?
Number of protons in the atom
What is mass number?
Total number of protons and neutrons in an atom
What are isotopes?
Atoms of the same element with different number of neutrons
Properties of alpha particle
Consist of two protons and two neutrons
relative mass 4 , relative charge is +2
What happens when an unstable nucleus emits an alpha particle?
Atomic number goes down by 2 , mass number goes down by 4
What is a beta particle?
High-speed electron from the nucleus, emitted when
a neutron in nucleus changes to proton and an electron
Representing beta particle
relative mass 0, relative charge -1
What happens when unstable nucleus emits a beta particle?
Proton stays in nucleus , atomic number goes up by 1
mass number is unchanged, electron instantly emitted
What happens when nucleus emits gamma radiation?
No change in atomic number or mass number
it is an electromagnetic wave released by nucleus. No charge and no mass
Neutrons are unchanged?
Neutrons emitted by some radioactive substances