1. Chemistry Unit Three Atomic Structure

2. A Brief History of the Atomic Theory

7. Gold Foil Experiment Rutherford’s

12. Atomic Structure Found in the Nucleus Found in the Nucleus Found outside the nucleus Has 1 amu of mass Has 1 amu of mass Has 0 amu of mass Has a positive charge Has a negative charge Has no charge (neutral) Electrons (e-) Neutrons (n) Protons (p+)

13. Atomic Structure Atom The number of protons in an atom never changes. Isotope Atoms of the same element that have different numbers of neutrons. Ion An atom that has lost or gained electrons .

16. 6 C 12.011 Atomic Number = 6 6 protons = 6 electrons 6 p+ = 6 e- (atom is neutral) Atomic Mass = 12 12 p+ and n -6 p+ 6 neutrons Calculating Numbers of Protons, Neutrons and Electrons.

17. Practice Calculating p+, n, e- *Atomic # is number of protons so protons = 47 *number (+) charges (p+) must equal (–) charges to make the atom neutral so electrons = 47 *Mass Number is total particles with mass (p+ and n) so 47 + 61 = 108 47 47 108 61 47 Silver # neutron # electron # proton Mass Number Atomic number Element

18. B Practice Calculating p+, n, e- *number of protons is the atomic # so atomic number is 29 *number (+) charges (p+) must equal (–) charges to make the atom neutral so electrons = 29 *Mass Number is total of all particles with mass (p+ and n) so subtract away the atomic number (#p+) and you will have just neutrons (64 – 29 = 35) 35 29 29 29 64 Copper # neutron # electron # proton Mass Number Atomic number Element

21. Bohr Model of Lithium 3 4 e - e - e - 3 Li 6.941

22. Bohr Model of Argon 18 22 e - e - e - 18 Ar 39.948 e - e - e - e - e - e - e - e - e - e - e - e - e - e - e -

27. s and p Orbital Electrons

28. d Orbital Electrons

29. f Orbital Electrons

30. Periodic Table to remember order s 1 s 2 s 2 p 1 p 2 p 3 p 4 p 5 p 6 d 1 d 2 d 3 d 4 d 5 d 6 d 7 d 8 d 9 d 10 f 1 f 2 f 3 f 4 f 5 f 6 f 7 f 8 f 9 f 10 f 11 f 12 f 13 f 14 Sublevels (s,p,d,f) by columns - Energy levels by rows (1,2,3,4,5,6,7 except d(row-1) & f(row-2)) 1 2 3 4 5 6 7 X – 1s 2 2s 2 2p 6 3s 2 3p 4 (16 e-) Y – 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 10 4p 6 5s 1 (36 e-) X Y

36. Lewis Dot Structures Con’t B B = Kernel (The protons, neutrons and full electron shells.) Valence shell electrons

40. Ne 1 2 3 4 5 6 7 8 So, it goes like this…

42. Average Atomic Mass (How the number ends up on the periodic table!!) 1 st  Mass of one isotope x % abundance in decimal form (watch SIG FIGS!!) 2 nd  Do this for each isotope of that element 3 rd  Then add all individual isotopes together to get the average atomic mass.

43. 1. Calculate the average atomic mass of potassium using the following data: Potassium-39 38.964 amu x 0.9312 = 36.28 amu Potassium-41 40.962 amu x 0.0688 2.82 amu = + Average atomic mass for K = 39.10 amu 6.88 % 40.962 amu Potassium-41 93.12% 38.964 amu Potassium-39 % abundance Mass Isotope

44. 2. Calculate the average atomic mass of magnesium using the following data: Magnesium-24 23.985 amu x 0.7870 = 18.88 amu Magnesium-25 24.986 amu x 0.1013 2.531 amu = + Average atomic mass for K = 24.31 amu + Magnesium-26 25.983 amu x 0.1117 = 2.902 amu 11.17 % 25.983 amu Magnesium-26 10.13 % 24.986 amu Magnesium-25 78.70% 23.985 amu Magnesium-24 % abundance Mass Isotope