1. ElementSymbol Atomic Number Atomic Mass # Protons # Electrons # Neutrons OXYGEN O COBALT Co LEAD Pb

2. ElementSymbol Atomic Number Atomic Mass # Protons # Electrons # Neutrons OXYGEN O8 COBALT Co LEAD Pb

3. ElementSymbol Atomic Number Atomic Mass # Protons # Electrons # Neutrons OXYGEN O816 COBALT Co LEAD Pb

4. ElementSymbol Atomic Number Atomic Mass # Protons # Electrons # Neutrons OXYGEN O8168 COBALT Co LEAD Pb

5. ElementSymbol Atomic Number Atomic Mass # Protons # Electrons # Neutrons OXYGEN O81688 COBALT Co LEAD Pb

6. ElementSymbol Atomic Number Atomic Mass # Protons # Electrons # Neutrons OXYGEN O816888 COBALT Co LEAD Pb

7. ElementSymbol Atomic Number Atomic Mass # Protons # Electrons # Neutrons OXYGEN O816888 COBALT Co27 LEAD Pb

8. ElementSymbol Atomic Number Atomic Mass # Protons # Electrons # Neutrons OXYGEN O816888 COBALT Co2759 LEAD Pb

9. ElementSymbol Atomic Number Atomic Mass # Protons # Electrons # Neutrons OXYGEN O816888 COBALT Co275927 LEAD Pb

10. ElementSymbol Atomic Number Atomic Mass # Protons # Electrons # Neutrons OXYGEN O816888 COBALT Co275927 LEAD Pb

11. ElementSymbol Atomic Number Atomic Mass # Protons # Electrons # Neutrons OXYGEN O816888 COBALT Co275927 32 LEAD Pb

12. ElementSymbol Atomic Number Atomic Mass # Protons # Electrons # Neutrons OXYGEN O816888 COBALT Co275927 32 LEAD Pb82

13. ElementSymbol Atomic Number Atomic Mass # Protons # Electrons # Neutrons OXYGEN O816888 COBALT Co275927 32 LEAD Pb82207

14. ElementSymbol Atomic Number Atomic Mass # Protons # Electrons # Neutrons OXYGEN O816888 COBALT Co275927 32 LEAD Pb8220782

15. ElementSymbol Atomic Number Atomic Mass # Protons # Electrons # Neutrons OXYGEN O816888 COBALT Co275927 32 LEAD Pb8220782

16. ElementSymbol Atomic Number Atomic Mass # Protons # Electrons # Neutrons OXYGEN O816888 COBALT Co275927 32 LEAD Pb8220782 125

17.  Atomic Number = ______________

18.  Atomic Number = # protons  Atomic Mass = _______________

19.  Atomic Number = # protons  Atomic Mass = # protons + # neutrons  Neutrons = __________________

20.  Atomic Number = # protons  Atomic Mass = # protons + # neutrons  Neutrons = Atomic Mass – # protons

21.  In an uncharged atom, the number of protons is the same as the number of ____________.  electrons  An uncharged atom has NO charge. Why?  Protons = electrons Isotopes 10/29/08 Review Atomic Number = Protons Atomic Mass = Protons + Neutrons Neutrons = Atomic Mass – Protons

22.  What is the difference between these 2 atoms?  Are they the same element?

23.  There can be different types (varieties) of an element  An isotope is a different form of an element but with a different number of neutrons  Same # of protons (same atomic number)

24.  If the number of neutrons is different, what else is different about the element?  Atomic Mass = protons + neutrons  If the number of neutrons is different, the atomic mass is also different

25.  In an uncharged atom, the number of protons is the same as the number of ____________.  electrons  An uncharged atom has NO charge. Why?  Protons = electrons Isotopes 10/29/08 Review Atomic Number = Protons Atomic Mass = Protons + Neutrons Neutrons = Atomic Mass – Protons Isotopes Different forms of an element - Element with different # of neutrons - Atomic number is still the same

26.  Not all elements have isotopes  If isotopes exist, the most common form of the element is the one found on the periodic table

27.  In an uncharged atom, the number of protons is the same as the number of ____________.  electrons  An uncharged atom has NO charge. Why?  Protons = electrons Isotopes 10/29/08 Review Atomic Number = Protons Atomic Mass = Protons + Neutrons Neutrons = Atomic Mass – Protons Isotopes Different forms of an element - Element with different # of neutrons - Atomic number is still the same - # of proton is the same - Atomic Mass is different - most common form found on periodic table

28.  Isotopes are abbreviated with the element and the atomic mass  Example: Helium-3 (He-3)  the atomic mass is 3  how many neutrons does it have? Atomic mass – protons 3 – 2 = 1

29.  In an uncharged atom, the number of protons is the same as the number of ____________.  electrons  An uncharged atom has NO charge. Why?  Protons = electrons Isotopes 10/29/08 Representing Isotopes Element + Atomic Mass EX. Helium-3

30.  In an uncharged atom, the number of protons is the same as the number of ____________.  electrons  An uncharged atom has NO charge. Why?  Protons = electrons Isotopes 10/29/08 Representing Isotopes Element + Atomic Mass EX. Helium-3 EX 1: Hawkium-10 (Hk) has an atomic number of 5 and a mass number of 10. Examples # protons:

31.  In an uncharged atom, the number of protons is the same as the number of ____________.  electrons  An uncharged atom has NO charge. Why?  Protons = electrons Isotopes 10/29/08 Representing Isotopes Element + Atomic Mass EX. Helium-3 EX 1: Hawkium-10 (Hk) has an atomic number of 5 and a mass number of 10. Examples # protons: 5 # electrons:

32.  In an uncharged atom, the number of protons is the same as the number of ____________.  electrons  An uncharged atom has NO charge. Why?  Protons = electrons Isotopes 10/29/08 Representing Isotopes Element + Atomic Mass EX. Helium-3 EX 1: Hawkium-10 (Hk) has an atomic number of 5 and a mass number of 10. Examples # protons: 5 # electrons: 5 # neutrons:

33.  In an uncharged atom, the number of protons is the same as the number of ____________.  electrons  An uncharged atom has NO charge. Why?  Protons = electrons Isotopes 10/29/08 Representing Isotopes Element + Atomic Mass EX. Helium-3 EX 1: Hawkium-10 (Hk) has an atomic number of 5 and a mass number of 10. Examples # protons: 5 # electrons: 5 # neutrons: 5

34.  In an uncharged atom, the number of protons is the same as the number of ____________.  electrons  An uncharged atom has NO charge. Why?  Protons = electrons Isotopes 10/29/08 EX 2: Hawkium-12 (Hk) has an atomic number of 5 and a mass number of 12. Examples # protons: # electrons: # neutrons:

35.  In an uncharged atom, the number of protons is the same as the number of ____________.  electrons  An uncharged atom has NO charge. Why?  Protons = electrons Isotopes 10/29/08 EX 2: Hawkium-12 (Hk) has an atomic number of 5 and a mass number of 12. Examples # protons: 5 # electrons: # neutrons:

36.  In an uncharged atom, the number of protons is the same as the number of ____________.  electrons  An uncharged atom has NO charge. Why?  Protons = electrons Isotopes 10/29/08 EX 2: Hawkium-12 (Hk) has an atomic number of 5 and a mass number of 12. Examples # protons: 5 # electrons: 5 # neutrons:

37.  In an uncharged atom, the number of protons is the same as the number of ____________.  electrons  An uncharged atom has NO charge. Why?  Protons = electrons Isotopes 10/29/08 EX 2: Hawkium-12 (Hk) has an atomic number of 5 and a mass number of 12. Examples # protons: 5 # electrons: 5 # neutrons: 7 How do we know that Hawkium-12 and Hawkium-10 are isotopes? Hawkium-12 and Hawkium-10 are isotopes - same atomic number - different atomic mass  different # neutrons

38.  Find the following information for Nitrogen-13, Nitrogen-14, and Nitrogen-15  Atomic Number:  Atomic Mass:  # Protons:  # Electrons:  # Neutrons:  Which isotope is the most common form of Nitrogen?