Atomic Structure

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Atomic Structure

• The smallest part of an element is an
  _____________________
• All atoms consist of subatomic particles
• ________________
• ________________
• ________________

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Nucleus

• The ___________of the atom
• Contains ______________________of the atom
• ____________ and ____________ are found ______
  the nucleus of an atom
• Mass Number ___________________________

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Protons

• _________________________________
• __________________________________
• 1 proton 1 atomic mass unit (amu)
• protons ________________________

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Neutron

• _______________________________
• Found in the _______________
• 1 neutron 1 amu
• neutrons ____________________________

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Electrons

• __________________________________
• Found in the ____________________
• Electrons have a very small mass, so we dont
  even count it!
• Electrons give atoms their _______________________
  ________
• Atoms are neutral so ____________________________
  ______

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Shorthand Notation
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Isotopes

• Atoms of the _________________with
  ________________________________.

• Nuclear symbol

• Hyphen notation ______________

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ationsarts/pages/chem
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Isotopes
Electrons
Nucleus
Electrons
Neutrons Protons Electrons
Neutrons Protons Electrons
Nucleus
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6Li 7Li
Electrons
Electrons
Nucleus
Nucleus
Neutrons Protons Electrons
Neutrons Protons Electrons
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Isotopes

• Chlorine-37
• atomic
• mass
• of protons
• of electrons
• of neutrons

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ationsarts/pages/chem
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Relative Atomic Mass

• 12C atom 1.992 10-23 g

• atomic mass unit (amu)
• 1 amu 1/12 the mass of a 12C atom

Neutron

• 1 p 1.007276 amu1 n 1.008665 amu1 e-
  0.0005486 amu

Electrons
Nucleus
Proton
Nucleus
Carbon-12
Neutrons 6 Protons 6 Electrons 6
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Average Atomic Mass

• weighted _________ of all ________
• on the Periodic Table
• round to _________ decimal places

Avg. Atomic Mass
(mass)() (mass)()

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ationsarts/pages/chem
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Calculating Average Atomic Mass

• You will be given the ____________and the
  ____________________(how common the isotope is in
  nature) of the isotope

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Average Atomic Mass

• EX Calculate the avg. atomic mass of oxygen if
  its abundance in nature is 99.76 16O, 0.04 17O,
  and 0.20 18O.

Avg. Atomic Mass


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ationsarts/pages/chem
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Example

• Carbon has 6 protons and 6 neutrons, what is
  Carbons mass number?
• An isotope of Carbon has 6 protons and 8
  neutrons, what is carbons mass number?
• Remember the number of __________ NEVER changes
  for an element!

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Example

• Carbon has 6 protons and 6 neutrons, what is
  Carbons mass number?
• C-12
• An isotope of Carbon has 6 protons and 8
  neutrons, what is carbons mass number?
• C-14
• Remember the number of protons NEVER changes for
  an element!

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Isotope Review

• Same element different number of
• __________________
• Different _________________
• Same _____________, therefore the same number of
  protons and electrons

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Atomic Structure

• ATOMS
• Differ by number of _____________
• IONS
• Differ by number of _____________
• ISOTOPES
• Differ by number of _____________

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Electrons

• Electrons give elements their ____________________
  ______________
• The arrangement of the electrons will determine
  how it _________ with other substances
• Gain electron the atom becomes _______
  (_______________)
• Lose an electron the atom becomes ___________
  (________________)

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Electrons are found in the ______________

• The cloud has regions of space called energy
  levels
• The first energy level holds ____ electrons
• The second energy level holds _____ electrons.
• The third energy level holds ____ electrons

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Valence Electrons

• Are found _______________________
• Dictate the _________ and ___________
  ________________ of an element
• Use the periodic table to determine the number of
  valence electrons.

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Lewis Dot Diagram

• A way to illustrate the number of valence
  electrons
• Use _______for each valence electron
• Place the dot ______ each side of the symbol
  before pairing the electrons
• The __________ represents the nucleus plus all
  the inner electrons for the element.

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Examples

• H
• O
• N
• F
• Ne

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Electrons and Light

• Electrons are normally in the ____________________
  __________
• When the atom is given ___________ the electrons
  move to the ___________ state.
• When the electrons ________ this energy they fall
  back to the ground state and emit
  _______________.
• Each element has a unique ________________________
  ___

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Electromagnetic Spectrum

• Electromagnetic Radiation
• A broad range of energetic emissions
• made up of photons
• Photons bundles of energy
• Travel like waves
• Move at the speed of light 3.0 x 108 m/s
• Electromagnetic waves do not require a medium to
  move

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Parts of the wave

• Amplitude the height of the wave
• Wavelength the distance between the two
  successive waves
• Frequency the number of waves that pass a given
  reference point per second

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• Wavelength lamda in units of nm
• Frequency nu in units of 1/s or s-1

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What is the difference between these waves?