1. UNIT VIII Atoms and the Periodic Table Lesson#1 Atomic Number, Atomic mass, Isotopes review

2. VIII.1 THE STRUCTURE OF THE ATOM Some vocabulary: PROTONS: NEUTRONS: * Elements are differentiated from one another by the number of protons in the nucleus

3. VIII.1 THE STRUCTURE OF THE ATOM ELECTRONS: ATOMIC NUMBER:

4. W HAT THE PERIODIC TABLE TELLS YOU … Atomic mass:

5. What if the atom is NOT neutral??? It means it is an _______

6. VIII.1 THE STRUCTURE OF THE ATOM ION: when electrons are added or taken away from an atom, an ion is formed (with a charge) Ex: If an extra electron is added to a neutral Cl atom: # protons: # electrons: Charge on nucleus: Charge of Electrons: Total Charge of Atom:

7. VIII.1 THE STRUCTURE OF THE ATOM

9. Ex: If 2 electrons (e - ) are removed from Barium (Ba) # protons: # electrons: Charge on nucleus: Charge of Electrons: Total Charge of Atom:

10. VIII.1 THE STRUCTURE OF THE ATOM Ex: How many electrons are possessed by Ca 2+ ? How many protons are in Ca +2 ?

11. VIII.1 THE STRUCTURE OF THE ATOM Atomic mass: Atomic number: # Neutrons = (ATOMIC MASS) - (ATOMIC NUMBER)

12. VIII.1 THE STRUCTURE OF THE ATOM Ex: Find the number of protons, neutrons and electrons possessed by the following atoms: a. C b. Zn 3+

13. VIII.1 THE STRUCTURE OF THE ATOM Isotopes: Atoms with same # of protons, but different # of neutrons ; therefore different atomic mass! If you add a proton to an atom, a new element is produced: C + p → N If you add a neutron to an atom, you get the same element but heavier; in other words an isotope! C + n → C

14. VIII.1 THE STRUCTURE OF THE ATOM Three H-isotopes: 1. H = H = Hydrogen 2. H = D = Deuterium 3. H = T = Tritium C-isotopes:

15. VIII.1 THE STRUCTURE OF THE ATOM E. Natural Mixtures of Isotopes Molar Mass --- is really an average value for a MIXTURE of isotopes

16. VIII.1 THE STRUCTURE OF THE ATOM Ex: The following mixtures of isotopes are found in nature – calculate the expected molar mass of a the mixture. a) Ga-69 = 60.0%, Ga-71 = 40.0%

17. VIII.1 THE STRUCTURE OF THE ATOM b) Ag-107 = 51.8%, Ag-109 = 48.2%

18. H OMEWORK Hebden p. 146 # 13-17 p. 147 #19 (fill in table) p. 149 # 22 (fill in table) p. 150 #23 a, d and 24