1. 1) 2 or more elements chemically combined (atoms linked) Sodiumchlorinesalt 2) Properties of a compound are TOTALLY different from the properties of the elements that form them PROPERTY EXAMPLES

2. 3) Energy (heat, light, electricity) is involved to make or to separate them 4) every Compound has a formula (Example : NaCl or H 2 O 5) Elements in a compound are in specific proportions 6) The smallest part of a compound is a molecule www.youtube.com/watch?v=mHQpU_GLfFk

3. Subscript- tells how many atoms if each element H 2 + O = H 2 OWater Na + Cl = NaClSalt Coefficient- large number in front and tells the number of molecules 3 CO 2 = 3 molecules of Carbon Dioxide Other info

4. H H Water Molecule Water is a compound made of two 2 atoms of hydrogen and 1 atom of oxygen. One molecule of water has the same properties as a bucket full of water O Molecules are the smallest particle of a compound & has all the properties of that compound

5. Molecules of elements Sometimes elements are found in nature as molecules Hydrogen = H 2 Oxygen = O 2 Nitrogen = N 2 Chlorine = Cl 2 HH Drawing chemical equations Hydrogen Oxygen NN OO Nitrogen

6. A chemical equation is a CHEMICAL REACTION Ammonia: 1 atom of nitrogen, 3 atoms of hydrogen –Chemical equation = NH 3 Silver nitrate: 1 silver, 1 nitrogen, 3 oxygen –Chemical equation = AgNO 3 Carbon dioxide: 1 carbon, 2 oxygen –Chemical equation = CO 2