Chemistry

• Atom - the smallest chemically divisible unit of an element, from which all substances are made
• Element - a substance that contains one type of atom
• Compound - two or more different elements chemically joined together
• Mixture - two or more elements mixed together but not chemically combined
• Molecule - a small group of atoms chemically bonded together, with a finite structure
• Groups = columns
• Periods = rows
• Group 1 = alkali metals
• Group 2 = alkaline earth metals
• Group 7 = halogens
• Group 8/0 = noble gases
• Mercury and bromine are liquid at room temperature.
• Boron, silicon, etc. form the diagonal line that separates non-metals from metals
• Boron, silicon, germanium, arsenic, and tellurium are semi-metals
• The Periodic Table is ordered by atomic number. This is the number of protons in the nucleus.
• The atomic mass tells you the quantity of matter contained in an atom of the element. It is usually found on the bottom of an element in the periodic table. On our periodic tables, however, it is usually located on top.
• Non-metals are mainly found on the right of the Periodic Table
• A physical property is a characteristic of a substance that can be observed without changing the substance.