1. 1 The Atom Atomic Number and Mass, Isotopes

2. 2 Elements Pure substances that cannot be separated into different substances by ordinary processes Are the building blocks of matter 112 elements known today Examples: carbon gold calcium

3. 3 Symbols of Elements Use 1 or 2 letter abbreviations Capitalize the first letter only Examples: C carbon Cocobalt N nitrogenCacalcium F fluorine Br bromine O oxygen Mg magnesium

4. 4 Symbols from Latin Names ElementSymbolLatin name CopperCucuprum GoldAuaurum LeadPbplumbum MercuryHghydrargyrum PotassiumKkalium SilverAgargentum SodiumNanatrium TinSnstannum

5. 5 % Major Elements in the Body O65.0 %K 0.34 C18.0S 0.26 H10.0Na 0.14 N 3.0Cl 0.14 Ca 1.4Fe 0.004 P 1.0 Zn 0.003 Mg 0.50 Trace Elements As, Cr, Co, Cu, F, I, Mn, Mo, Ni, Se, Si, V

6. 6 Learning Check Select the correct symbol for each: A. Calcium 1) C2) Ca3) CA B. Sulfur 1) S2) Sl3) Su C. Iron 1) Ir2) FE3) Fe

7. 7 Solution Select the correct symbol for each: A. Calcium 2) Ca B. Sulfur 1) S C. Iron 3) Fe

8. 8 Learning Check Select the correct name for each: A. N 1) neon2) nitrogen 3) nickel B. P 1) potassium2) phogiston 3) phosphorus C. Ag 1) silver2) agean3) gold

9. 9 Solution Select the correct name for each: A. N 2) nitrogen B. P 3) phosphorus C. Ag 1) silver

10. 10 Periodic Table Represents physical and chemical behavior of elements Arranges elements by increasing atomic number Repeats similar properties in columns known as chemical families or groups

11. 11 Subatomic Particles ParticleSymbol Charge Relative Mass Electron e - 1- 0 Proton p + + 1 Neutron n0 1

12. 12 Location of Subatomic Particles 10 -13 cm electrons protons neutrons 10 -8 cm nucleus

13. 13 Atomic Number Counts the number of protons in an atom

14. 14 Periodic Table 1 2 3 4 5 6 7 8 11 Na

15. 15 Atomic Number on the Periodic Table 11 Na Atomic Number Symbol

16. 16 All atoms of an element have the same number of protons 11 Na 11 protons Sodium

17. 17 Learning Check AT 1 State the number of protons for atoms of each of the following: A. Nitrogen 1) 5 protons 2) 7 protons 3) 14 protons B. Sulfur 1) 32 protons 2) 16 protons 3) 6 protons C. Barium 1) 137 protons 2) 81 protons 3) 56 protons

18. 18 Solution AT 1 State the number of protons for atoms of each of the following: A. Nitrogen 2) 7 protons B. Sulfur 2) 16 protons C. Barium 3) 56 protons

19. 19 Number of Electrons An atom is neutral The net charge is zero Number of protons = Number of electrons Atomic number = Number of electrons

20. 20 Mass Number Counts the number of protons and neutrons in an atom

21. 21 Atomic Symbols Show the mass number and atomic number Give the symbol of the element mass number 23 Na sodium-23 atomic number 11

22. 22 More Atomic Symbols 163165 O P Zn 81530 8 p + 15 p + 30 p + 8 n16 n35 n 8 e - 15 e - 30 e -

23. 23 Isotopes Atoms with the same number of protons, but different numbers of neutrons. Atoms of the same element (same atomic number) with different mass numbers Isotopes of chlorine 35 Cl 37 Cl17 chlorine - 35 chlorine - 37

24. 24 Learning Check AT 2 Naturally occurring carbon consists of three isotopes, 12 C, 13 C, and 14 C. State the number of protons, neutrons, and electrons in each of these carbon atoms. 12 C 13 C 14 C 6 6 6 #P _______ _______ _______ #N _______ _______ _______ #E _______ _______ _______

25. 25 Solution AT 2 12 C 13 C 14 C 6 6 6 #P __6___ _ 6___ ___6___ #N __6___ _ _7___ ___8___ #E __6___ _ 6___ ___6___

26. 26 Learning Check AT 3 An atom of zinc has a mass number of 65. A.Number of protons in the zinc atom 1) 302) 353) 65 B.Number of neutrons in the zinc atom 1) 302) 353) 65 C. What is the mass number of a zinc isotope with 37 neutrons? 1) 372) 653) 67

27. 27 Solution AT 3 An atom of zinc has a mass number of 65. A.Number of protons in the zinc atom 1) 30 B.Number of neutrons in the zinc atom 2) 35 C. What is the mass number of a zinc isotope with 37 neutrons? 3) 67

28. 28 Learning Check AT 4 Write the atomic symbols for atoms with the following: A. 8 p +, 8 n, 8 e - ___________ B.17p +, 20n, 17e - ___________ C. 47p +, 60 n, 47 e - ___________

29. 29 Solution AT 4 16 O A. 8 p +, 8 n, 8 e - 8 B.17p +, 20n, 17e - 37 Cl 17 C. 47p +, 60 n, 47 e - 107 Ag 47

30. 30 Learning Check AT 5 An atom has 14 protons and 20 neutrons. A.Its atomic number is 1) 142) 163) 34 B. Its mass number is 1) 142) 163) 34 C. The element is 1) Si2) Ca3) Se D.Another isotope of this element is 1) 34 X 2) 34 X 3) 36 X 16 14 14

31. 31 Solution AT 5 An atom has 14 protons and 20 neutrons. A.It has atomic number 1) 14 B. It has a mass number of 3) 34 C. The element is 1) Si D.Another isotope of this element would be 3) 36 X 14

32. 32 Masses of Atoms A scale designed for atoms gives their small atomic masses in atomic mass units (amu) An atom of 12 C was assigned an exact mass of 12.00 amu Relative masses of all other atoms was determined by comparing each to the mass of 12 C An atom twice as heavy has a mass of 24.00 amu. An atom half as heavy is 6.00 amu.

33. 33 Atomic Mass Listed on the periodic table Gives the mass of average atom of each element compared to 12 C Average atom based on all the isotopes and their abundance % Atomic mass is not a whole number Na 22.99

34. 34 Learning Check AT6 Using the periodic table, specify the atomic mass of each element (round to the tenths place): A.calcium__________ B. aluminum__________ C. lead__________ D. barium__________ E. iron__________

35. 35 Solution AT6 Using the periodic table, specify the atomic mass of each element (round to the tenths place): A.calcium_40.1 amu _ B. aluminum_27.0 amu _ C. lead_207.2 amu_ D. barium_137.3 amu_ E. iron_55.8 amu__

36. 36 Calculating Atomic Mass Percent(%) abundance of isotopes Mass of each isotope of that element Weighted average = mass isotope 1 (%) + mass isotope 2 (%) + … 100 100

37. 37 Atomic Mass of Magnesium Isotopes Mass of Isotope Abundance 24 Mg =24.0 amu 78.70% 25 Mg = 25.0 amu 10.13% 26 Mg = 26.0 amu 11.17% Atomic mass (average mass) Mg = 24.3 amu Mg 24.3