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Review for TEST on Chapters 3, (Atomic Structure (3-1, 3-2, 3-3 ) – no details on radioactivity
and nuclear
reactions) and Ch 4 ( Electron structure)

Chapter 3
3-1
Atoms: smallest particle of an element that retains the chemical identity of that
element
postulates of Dalton’s atomic theory:
atoms of one element are all same
Different element=different atom
Each element composed of atoms
Atoms are neither created/destroyed in any chemical reaction
Given compound always has same relative numbers and kinds of atoms
3-2
How is atomic structure related to electricity
Atoms contain particles that have electrical charge
what did studies of cathode rays and radioactivity show of nucleus
rutherford’s alpha-scattering experiment, nucleus
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static electricity: comes from electrical charges that are not in motion
Franklin lightning kite-flying experiment: object could have one of two
kinds of electric charge: +orElectrical current: moving stream of electrical charges
Cathode=negatively charged electrode
Anode=positively charge electrode
Radiation called cathode ray, tube itself called cathode ray tube/CRT
Complex version of a cathode ray tube=TV
Cathode ray=stream of particles, particles carried a negative charge
Thomson: atoms were not indivisible balls but instead had a
substructure, negative particles=electrons
Millikan: charge and mass of electron
Rutherford’s experiment: how alpha particles interact with thin metal
foils
Thomson’s “plum-pudding” model= negative charges are distributed
evenly throughout an atom’s positively charged interior
Rutherford’s model= all of an atom’s positive charge as well as most of
its mass is concentrated in core at atom’s center, nucleus

3-3
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3 subatomic particles: protons, neutrons, electrons
nucleus=P&N, space around nucleus=E
electrons do not orbit nucleus in a well-defined path
=>impossible to know exactly where an electron is at any given time
E’s positions=clouds
Atomic #=# of P=atom’s identity
Ion= when an atom loses/gains one or more electrons and acquires a
net electrical charge
Isotopes= same # of protons/atomic # but different # of neutrons/mass
Symbol: mass number, element symbol, atomic number
(mass at top)

• 1 atomic mass unit (amu)= 1/12 mass of 126C atom
number of protons, neutrons, electrons in atom/ion
define isotopes, atomic mass
Chapter 4
4-1
• light has both the properties of waves and particles
• four characteristics of an electromagnetic wave: amplitude, wavelength,
frequency, speed
• major regions of electromagnetic spectrum: invisible to human eye,
visible light=cosmic rays
• from lowest to highest frequency (highest to lowest wavelength)
radio, TV, micro, infrared, visible (ROYGBIV), UV, X-rays, gamma
• frequency: how fast the wave oscillates up and down (unit
cycles/second)
• wavelength: distance between successive crests
• speed: light, regardless of its wavelength, moves at constant speed of
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6261 x 10-34 J-s
Planck’s equation helped Einsten explain photoelectric effect
• photoelectric effect: electrons ejected from surface of metal when light
shines on metal
• for each metal, minimum frequency of light is needed to release
electrons
=> red light is incapable of releasing E even if light is very intense;
violet light, even if it is faint, releases E easily
• Einstein=light consists of quanta of energy that behave like tiny
particles of light=photons
• Each photon carries energy given by E=hv
• Photon strikes metal=transfers energy to E in metal atom
=>either E “swallows” entire photon or none of it= E cannot use just
part of energy from photon, cannot collect energy from several photons
• Energy (and thus frequency) of photon is important, not # of photons
(intensity of light)
Compton effect

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Compton effect helped prove dual nature theory of light
Photon
=>particle-speed of light, associated frequency and wavelength

4-3
Line spectrum: contains only certain colors/wavelengths
For every element, emitted light contains only certain wavelengths,
giving each element a unique line spectrum
• Line spectrum also referred to as atomic emission spectrum of
element=atomic fingerprint useful in identifying elements
• Color of flame=characteristic of element (ex
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visible light
Bohr Model
Main idea: energies of E in atoms are quantized
• Bohr Model: to get spectral lines, energy of E in atom must be
quantized
• Labeled each energy level, each orbit by quantum number n
• Lowest energy level=ground state, n=1, orbit closest to nucleus
• Excited state=when E absorbs appropriate amount of energy and
jumps to higher energy level
n=2,3,4, …
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spins=paired

4-5
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electron configuration: distribution of E among orbitals of atom
when atoms encounter each other, their E come in contact
=>these contacts often cause atoms to bond, formation of molecules,
ions
Aufbau principle: E are added one at a time to lowest energy levels
available until all E of atom have been accounted for
Pauli Exclusion principle: orbital can hold 2E max
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directions=paired
=>single E in orbital=unpaired
Hund’s rule: E occupy equal-energy orbitals so max

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