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Atomic Number Number of Protons. Mass Number Number of Protons + Neutrons.

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Presentation on theme: "Atomic Number Number of Protons. Mass Number Number of Protons + Neutrons."— Presentation transcript:

1 Atomic Number Number of Protons

2 Mass Number Number of Protons + Neutrons

3 12 C Left Superscript = mass number 6

4 12 C Left Subscript = atomic number 6

5 80 Br 35 Atomic Number = ?

6 20 Ne 20 10 Mass Number = ?

7 27 Al 27 13 Mass Number = ?

8 40 Ca 20 Atomic Number = ?

9 Isotope Atoms of the same element with a different # of neutrons

10 Characteristics of Proton Charge = +1, mass = 1 amu, location = inside nucleus

11 Characteristics of Neutron Charge = 0, mass = 1 amu, location = inside nucleus

12 Characteristics of Electron Charge = -1, mass = 1/1836 amu or 0.0005 amu, location = outside nucleus

13 Ion An atom that has gained or lost electrons & so carries charge

14 Nucleons Protons & Neutrons

15 atom Smallest bit of an element that retains the properties of the element.

16 atom Electrically neutral. # of protons = # of electrons.

17 Charge # protons - # electrons

18 # of neutrons Mass number – atomic number

19 14 C 8 6 # of neutrons = ?

20 9 Be 5 4 # of neutrons = ?

21 40 Ar 22 18 # of neutrons = ?

22 15 N 8 7 # of neutrons = ?

23 24 Mg Right superscript = charge 12 2+

24 24 Mg 10 electrons 12 2+ # of electrons?

25 86 Rb 36 electrons 37 1+ # of electrons?

26 127 Te 53 electrons 52 1- # of electrons?

27 32 S 18 electrons 16 2- # of electrons?

28 Cation Positive ion: atom lost electrons

29 Anion Negative ion: atom gained electrons

30 Avg. Atomic Mass Weighted avg. of masses of naturally occurring isotopes of an element.

31 2 isotopes of Cl: 75% Cl-35 & 25% Cl-37. Calculate avg. atomic mass. Avg. atomic mass =.75(35) +.25(37) = 35.5 amu

32 Dalton’s Model Billiard Ball Model

33 Thomson’s Model Plum Pudding Model - - - - - + + + + +

34 Rutherford’s Model Nuclear Model - - -

35 Rutherford’s Experiment Source: http://www.dlt.ncssm.edu/TIGER/chem1.htm#atomic

36 Rutherford’s Experiment: Results 1)Most of the alpha particles went straight through.  Most of the atom is empty space. 2)Some of the alpha particles were deflected back.  The nucleus was tiny, but contained most of the mass of the atom.

37 Bohr’s Model Planetary Model

38 Schrodinger’s Model Modern or Quantum Mechanical Model Source: http://www.dlt.ncssm.edu/TIGER/chem1.htm #atomic

39 Bohr Configuration Ground state configurations found in reference tables. Cannot be predicted.

40 Bohr Configuration of Na = 2-8-1 2 electrons in energy level 1 8 electrons in energy level 2 1 electron in energy level 3

41 Bohr Diagram of Na +11

42 Bohr Model Electrons are restricted to specific orbits or shells or principle energy levels. Each shell holds a specific # of electrons. Each shell has a specific energy & radius. Energy of electron must match energy of shell.

43 Maximum Capacity of Bohr Levels Shell #Max # of electrons 1 2 3 4 n 2 8 18 32 2n 2

44 Ground State Bohr model Every electron is in the lowest available orbit.

45 Excited State Bohr model An electron has absorbed heat, light, or electrical energy and moved to a higher energy level. Unstable. Returns to ground state quickly by emitting a photon.

46 Continuous Spectrum Spectrum produced by holding a prism in sunlight. Contains light at every wavelength.

47 Bright Line Spectrum Visible light produced by electrons in atom returning to ground state: light of only a few wavelengths is present. Each element has a unique bright line spectrum. Used to identify elements. Wavelengths of bright lines correspond to difference between energy levels. Source: http://www.dlt.ncssm.edu/TIGER/chem1.htm#atomic

48 Absorbtion of Energy h Ground state Excited state E1E1 E2E2 E3E3

49 Emission of Energy h Ground state Excited state E1E1 E2E2 E3E3

50 Orbital Modern Model Region of space that holds 2 electrons. Has a specific energy. Shapes vary.


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