1. Atoms are made of protons, neutrons and electrons.
2. Protons and electrons have equal and opposite electric charges, Protons are positively charged, and electrons are negatively charged.
3. Atoms are arranged in the periodic table in order of thier atomic number.
4. Neutrons have no electric charge. They are neutral.
In the nucleus of atoms there are protons and neutrons. Around the nucleus there are electrons which have a negative charge. In the periodic table, atoms are arranged in order of their atomic number.