Atoms are the building blocks that make up matter Matter is anything that has mass and takes up space Tiny atoms form all matter They are so small that millions of atoms would fit on the head of a pin 6
Individual atoms have even smaller particles called protons electrons and neutrons An atom’s protons and neutrons are found in its center the nucleus Electrons orbit the nucleus like the planets around the Sun _ atom _ nucleus _ _ 7 _ _ _ electron neutron proton
Protons and electrons have an electrical charge Protons have a positive charge while electrons have a negative charge Opposite charges attract each other like magnets Therefore protons attract electrons At the same time like charges repel each other Protons repel protons while electrons repel electrons protons electrons Protons attract electrons due to their opposite charge Because of their like charge electrons repel electrons and protons repel protons 8
Atoms start with an equal number of protons and electrons The protons positive charges offset the electrons negative charges The atom’s charge is neutral electron neutron proton nucleus 9
