physical science

• Dmitri Mendeleev - made the periodic table
• Periodic Table - shows all known elements in the universe
• Atomic Number - The number of protons found in the nucleus of an atom or The number of electrons surrounding the nucleus of an atom.
• Symbol - The number of electrons surrounding the nucleus of an atom.
• Atomic Weight - The number of protons and neutrons in the nucleus of an atom.
• # of PROTONS     = ATOMIC NUMBER

  # of ELECTRONS = ATOMIC NUMBER

  # of NEUTRONS = ATOMIC WEIGHT - ATOMIC NUMBER
• Element - A substance composed of a single kind of atom. Cannot be broken down into another substance by chemical or physical means.
• Compound - A substance in which two or more different elements are CHEMICALLY bonded together.
• Mixture - Two or more substances that are mixed together but are NOT chemically bonded.
• The elements are organized by:

  -Atomic number

  -Chemical Properties
• Group( or Family) - a vertical column. Elements in groups have similar chemical properties.
• Period - a horizontal row.
• There are 7 periods.
• There are 18 numbered columns.
• International Union of Pure and Applied Chemistry (IUPAC) - 1985 new system for labeling groups.
• Elements can be classified into:

  -Metals

  -Nonmetals

  -Metalloids (semimetals)
• Good conductors of electricity and heat. Malleable (can be hammered into sheets). Ductile (can be drawn into wires). Lustrous. - Physical properties of metals
• Easily lose electrons. Form positive (+) ions. - Chemical properties of metals
• Gain electrons. Form negative ions. - nonmetal chemical properties
• They do not have the properties of metals. - Nonmetal Physical Properties
• The periods (rows) of the periodic table indicate the highest energy level occupied by one or more electrons.
• Valence Electrons - The electrons the occupy the highest energy level of an atom.
• The “A” groups are numbered 1-8.
•   Lithium, Sodium, Potassium, Rubidium, Cesium, Francium - Group 1- Alkali Metals
• Sodium’s Reaction with H2O Produces Hydrogen
• Reactivity of Alkali Metals Increases from top to bottom of the group.
• Sodium and Potassium are stored in oil to keep them from reacting with oxygen and water in the air.
• Cesium is stored in glass tubes of argon gas( an inert gas).
• Beryllium, Magnesium, Calcium, Strontium, Barium, Radium - Group 2- Alkali Earth Metals
• Be does not react with water.

  Mg reacts with hot water.

  Ca, Sr, Ba react easily with cold water.
• There is Mg in chrolophyll - C55H72O5N4Mg