u3: quantum mechanical model of atom Flashcards

1
Q

what did bohr’s model explain

A
  • periods result from filling of electron energy levels
  • period comes to end when max numer of electrons are reached for outer level
  • max number of electrons in each energy level are 2, 8, 18, etc
  • group number provides number of valence electrons
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2
Q

why didn’t bohrs model work?

A
  • explained one-electron systems, not more than 1 electron
  • some elements have many spectra lines: bohr didn’t explain those liknes
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3
Q

what did albert michaelson find in 1891 abt bohr’s model

A

main lines of bright spectrum for hydrogen were acc composed of many lines

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4
Q

zeeman effect

A

if gas discharge tube placed near strong magnet, some single lines split into new lines

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5
Q

what did de broglie find?

A
  • if light particles can behave like a wave, then all matter has internal wave-like properties
  • radius of orbit = integer number of wavelengths = quantized energy level that bohr calculated
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6
Q

why wasn’t the wave-like nature of particles not observed

A

large particles have v small wavelengths

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7
Q

how does a beam of electrons behave when passing through a crystal? what was bohr’s problem?

A
  • it diffracts the same way light diffracts when it passes through a glass prism
  • bohr’s problem was treating electrons as particles
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8
Q

limit of wavelength

A

size limit of wavelength still in contention

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9
Q

schrodinger’s contribution

A

used eqn that explain particle and wavelike nature of electrons

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10
Q

what did schrodinger suggest about emission spectra?

A

that it results from electrons transforming from one orbital waveform to another, NOT electrons jumping from one energy level to another

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11
Q

which quantum numbers describe the possible energy states of an electron? wht r these states known as?

A
  • n, l, ml, ms
  • known as atomc orbitals that predict the 3D space (cloud) where there is a high probability of finding an electron in an atom
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12
Q

what did heisenburgs math lead to?

A

uncertainty principle

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13
Q

uncertainty principle

A
  • position/speed of electron can’t be known w/ precision
  • schrodinger’s orbital is acc a space/cloud where there is high probability to find electron
    = quantum mechanical atomic model
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14
Q

what does the quantum mechanical model of the atom tell us?

A
  • emission spectra for diff. elements (transofrming waves)
  • why multivalent metal ions exist
  • why some elements are magnetic
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15
Q

what doesn’t the quantum mech model include?

A
  • atom has further subatomic particles
  • subatomic particles mad of further subatomic particles (quarks)
  • actinides don’t obey all of schrodinger’s rules when forming compounds
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16
Q

how are electrons arranged?

A
  • by energy levels
  • increasing from level 1 to level 7 period
17
Q

what do electrons occupy?

A

orbitals, not orbits

18
Q

what are orbitals

A
  • energy cloud where electron spends 90% of its time
  • not always circular in shape
19
Q

principal

A
  • n
  • size
  • 1 to infinity
  • to describe atomic orbital
20
Q

angular moment

A
  • l
  • shape
  • 0 to n-1
  • to describe atomic orbital
21
Q

magnetic

A
  • ml
  • orientation/position
  • -l to +l
  • to describe atomic orbital
22
Q

electron spin

A
  • ms
  • direction of electron spin
  • +/- 1/2
  • to describe electron in atomic orbital
23
Q

pauli exclusion principle

A

no two electrons can have same value for n, l, ml, ms bc only two electrons of opposite spins can occupy the same orbital

24
Q

how does n describe size of an atom?

A
  • larger integer = larger size
  • max. amnt of electrons tht energy level can occupy is 2n^2
25
Q

how do values of l describe shape?

A
  • 0 = s = sharp
  • 1 = p = principal
  • 2 = d = diffuse
  • 3 = f = fundamental
26
Q

subshell

A

collection of orbitals with same value of n and l

27
Q

s orbitals

A
  • spherical shaped
  • each s orbital can hold 2 electrons
  • s orbital for every enery level (called 1s, 2s, 3s, etc_
28
Q

p orbitals

A
  • dumb-bell shaped
  • start in 2nd enery level
  • p sublevel has 3p
  • each orbital can old 2 electrons
29
Q

d sublevel

A
  • starts in 3rd energy level
  • 5 diff shapes (orbitals)
  • each orbital holds 2 electrons
30
Q

f sublevel

A
  • has 7 F orbitals
  • starts in fourth energy level
  • has seven diff. shapes (orbitals)
  • 2 electrons per orbital
31
Q

the 3 orientations for p orbital

A
  • ml = -1 : along z-axis
  • ml = 0 : along x-axis
  • ml = 1 : along y-axis
32
Q

how many orientations do s-orbitals have?

A
  • 1
  • bc. l=0 so ml=0