Topic 4 - Metals and non-metals, atomic structure

ATOMIC STRUCTURE

• In the centre of each atom is the nucleus.
• The nucleus contains two sorts of particles, protons and neutrons. 
• The proton carries an positive electric charge.
• The neutron is neutral. 
• Electrons are outside the nucleus. They carry an negative electric charge. 
• An atom has no overall electric charge and contains equal numbers of protons and electrons. 
• atomic number (or proton number)= the number of protons in an atom. 
• isotopes= variations in the number of neutrons. Some isotopes are radioactive, meaning they decay with the emission of radiation. 
• The sum of the number of protons and neutrons in an atom is…