• Isotopes are atoms of the?same?element?that contain the same number of?protons?and electrons but a different number of?neutrons
• The symbol for an isotope is the?chemical?symbol?(or?word) followed by a?dash?and then the?mass?number
  • Eg. carbon-12 and carbon-14 are isotopes of carbon containing 6 and 8 neutrons respectively

The atomic structure and symbols of the three isotopes of hydrogen

• Isotopes have?similar chemical properties?but?different physical properties

Chemical properties

• Isotopes of the same element display the?same chemical characteristics
• This is because they have the same number of electrons in their?outer?shells
• Electrons take part in?chemical reactions?and therefore determine the?chemistry?of an atom

Physical properties

• The only difference between isotopes is the number of?neutrons
• Since these are neutral subatomic particles, they only add?mass?to the atom
• As a result of this, isotopes have different?physical properties?such as small differences in their?mass?and?density