1. ATOMS: number, mass, isotopes, properties rudy reiblein

2. The structure of the atom

3. The three particles which make up the atom:

4. ATOMIC NUMBER Each element has its own atomic number which corresponds to its number of protons. Examples: Hydrogen’s atomic # is 1 because it has only 1 proton Element #6 is carbon. All carbon atoms have 6 protons Element #29 is copper, it has 29 protons Any atom that has 79 protons must be gold.

5. -The mass of an atom is due to its protons and neutrons (since electrons have so little mass, their contribution is negligible). Therefore, Atomic mass = #protons + #neutrons and, in a neutral atom, #electrons = #protons

6. ISOTOPES: although all atoms of an element have the same number of protons, they do not have to have the same number of neutrons. Atoms that have the same number of protons but a different number of neutrons are said to be isotopes of that element. Example: there are three isotopes of hydrogen (fill in the blanks)

7. AVERAGE ATOMIC MASS: because almost all elements have several isotopes, a sample of any element will contain atoms with different atomic masses. For example, a sample of carbon in the form of graphite will have many atoms of carbon 12, but there will also be a few atoms of carbon 11 and carbon 14. The average mass of the atoms, therefore, will not be exactly 12; in fact it is a bit higher (12.01) because the number of carbon 14 atoms is enough to boost the average. The atomic number listed on the periodic table is the average of a typical sample of the element.

8. Making an element from its ore

10. Lithium reacts with water

14. Sodium reacts with water

15. Magnesium reacts violently with oxygen from the air if heated enough

19. Phosphorus reacts spontaneously with oxygen from the air.

23. Potassium is highly reactive.

25. Compounds: when elements react with each other, they bond together to form new sub-stances called compounds. All com-pounds are composed of more than one element. The subscript after each element tell you how many atoms of that element are in one molecule or unit of the compound.

26. Some common compounds