Particles, quantum phenomena and electricity

Every atom has a positively charged nucleus at its centre that is ssurrounded by negatively charged particles called electrons.
The nucleus of the atom is composed of protons and neutrons which have approximatety equal mass.
Protons and electrons have fixed equal and opposite anounts of charge, and neutrons are uncharged.
An uncharged atom has equal numbers of electrons and protons.
Radioactive substances emit radiation because the nuclei of the atoms are unstable.
The radiation from radioactive substances ionises substances it passes through.
There are three types of radiation from radioactive substances
- alpha radiation which is stopped by paper and is strongly ionising
- beta radiation which is stopped by 2-3mm thickness of…

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