matter

• Matter is made up of the smallest particles called molecules
• Molecules are made up of particles called atoms
• Solid


  • Molecules are packed closely together, move or vibrate back and forth in only one fixed position, have strong intermolecular forces, have definite shape and volume
• Liquid


  • Molecules are loosely packed with spaces in between, can roll, glide and take the shape of their container, have weaker intermolecular forces, can flow freely
• Gas


  • Molecules are far apart, constantly move in all directions, feel the shape of the container, have very weak intermolecular forces, have no definite shape or volume
• Atom


  The smallest particle of matter which cannot be further subdivided
• Each element is made up of one kind of atom that cannot be further subdivided
• Protons and neutrons are found in the nucleus of an atom, while electrons travel in definite orbits around the nucleus
• The number of protons and neutrons in an atom identifies the atom of an element
• The atomic number tells the number of electrons or protons present in an atom
• The atomic mass is the sum of the number of protons and neutrons in an atom
• Atoms combine to form molecules, which are still made up of smaller particles called atoms
• Atoms in molecules are held together by chemical bonds
• Molecule of water


  • 2 hydrogen atoms bonded to 1 oxygen atom
• A molecule can be a combination of the same kind of element or a combination of different kinds of elements