Atomic Structure - Protons, neutrons and electrons
Protons and neutrons make up the nucleus.
Electrons orbit the nucleus in shells.
Protons have a positive charge and electrons have a negative charge.
An atom has the same number of protons and electrons so that it is electrically neutral.
Atomic structure - Isotopes
Most elements are made up of a mixture of isotopes
Isotopes of the same element have;
- same number of protons and electron
- but different number of nutrons in the nucleus
- different masses
Carbon, for example exists as of isotopes.
C 12, C 13, C 14
Carbon 12, 13 and 14 will all have 6 electrons and 6 protons in however different number of neutrons.
You work it out by taking away its number of electrons and protons from its mass.
Number of protons and electrons is also known as the atomic number.
Different isotopes of the same element react in the same way because chemical reactions involve electrons . Neutrons make no difference to chemical activity
Atomic structure - Ions
- Many atoms react by gaining or losing electrons from charged particles called ions.
- Ions are charged because they have different numbers of protons and electrons
- Na + has one electron fewer than it's number of protons as one electron was removed.
- Cl - has one electrons more than it's number of prontons as it has gain an electron.