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Atomic Structure and Periodicity
Mr. Guerrero, AP Chemistry
Electromagnetic Radiation• Electromagentic Radiation(EM)- energy, in the form of
photons, that moves in waves as it travels through space.
• Examples of EM Radiation are:1 gamma rays 6 microwaves2 x-rays 7 radar waves 3 ultraviolet radiation 8 radio waves 4 visible light 5 infra-red radiation
Electromagnetic SpectrumElectromagnetic Spectrum
Electromagnetic Radiation
Figure 7.1
Wave measurements
• Crest- highest point of a wave cycle.• Trough – lowest point of a wave cycle. • Wavelength (l)– distance between two consecutive points
on a wave.• Amplitude – height of the wave, from the axis.• Frequency (n) – the number of wave cycles per second.
Wave measurements
Photons• All forms of Electromagnetic Radiation are
made up of photons.
• Photon (quantum)- a tiny packet of light energy that travels through space in electric and magnetic waves.
• Photons behave as both waves and particles.(Duality of Light Theory)
• Moving matter also has a wave-particle duality.• Discovered by Louis De Broglie• DeBroglie’s moving matter has a wavelength
lDeB = h = h p mv
h = Planck’s Constant, p = momentum = mass(kg) x velocity(m/s)
Find the DeBroglie wavelength of:
• A 2.35 kg bowing ball moving at 7.00 m/s.
• An electron travelling at ½ the speed of light.
• A 75 Kg football player running at 8.55 m/s.
Visible Light• All photons with a wavelength between
360 nm -740 nm.
Ultra violet(UV) visible light Infra-red(IR)
v i b g y o r 360 nm 740nm
Important Conversion
1 meter = 1 x 109 nanometers (memorize!)
Make each conversion:
364 nm = ______ meter
9.88 x 10 - 8 meter = ______nm
2000 nm = ______meter
0.0045 m = ________nm
Practice Problems c = • • Find the wavelength of a photon(light) if it has a
frequency of 8.1 x 1012 Hz.
• Find the frequency of a photon of light with a wavelength of 350 nm.
• Find the wavelength of a 6 x 1014 Hz photon and indicate its color.
• What is the frequency of a photon with
a wavelength of 895 nm?
Calculating the energy in a photon
E = hnEnergy = Planck’s Constant x frequency
Find the energy in a 1.8 x 1014 Hz photon.
Find the frequency of a 5.05 x 10-18 J photon.
Find the energy of a 485 nm photon.
Photon calculations
1) Find the energy of a 3.50 x 1014Hz photon.
2) What is the frequency of a 6.13 x 10-19 J photon?
3) A photon has a wavelength of 525 nm. What is the frequency?
4) What is the energy of this photon?
5) A photon has an energy of 1.05 x 10-18 J. Is this photon visible?
6) Which line series does this light belong to?
How are photons produced?
How are photons produced?
Line Spectra(pre-AP)• Each element has atoms with different
numbers of electrons.• As these electrons drop to lower energy
levels, they emit photons of unique wavelengths.
• Each element emits its own set of colored lines, called an emission line spectrum.
• These spectra are used to identify elements in unknown samples or composition of stars.
Hydrogen atom spectra series
n=2
n=3
n=4
n =2
n=6n=5
Line spectra seriesLyman Series- e- drops from n = X to n=1
lights are in Ultraviolet Region
Balmer Series- e- drops from n = X to n =2
lights are in Visible Region
Paschen Series- e- drops from n = X to n = 3
lights are in Infrared Region
Electron orbitals
• Orbital – a 3-dimensional space around the nucleus which can hold up to 2 electrons, with opposite spin.
*electrons are found in their orbitals 99.9% of the time.
Orbitals have different shapes: s, p, d, f
Orbitals have different shapes:
Orbital shape s spherical
p dumbbell
d clover or dumbbell/donut
f too complex
s-orbitals: spheres
p-orbitals: dumbbell
d-orbitals: clover (double dumbbell) or dumbbell/donut
f-orbitals: complex
Quantum Numbers
• The location of each electron in an atom can be determined by assigning each electron a four-number code called quantum numbers.
Important electron laws:
• Heisenberg Uncertainty Principle : the more accurately one knows the position of an electron the less accurately one can predict its momentum(speed) AND vice versa.
Important electron laws:
• Hund’s Rule: electrons fill empty orbitals first.• Aufbau Principle: electrons occupy orbitals in a certain
order: nearest to the nucleus first.• Pauli Exclusion Principle: No two electrons in the same
atom can have the same set of four quantum numbers.
4 Quantum Numbers:
• 1 Principal Quantum Number (n), gives the energy level (aka shell) of the electron.
• 2 Orbital Quantum Number (l) = gives the shape of orbital of the electron.
• 3 Magnetic Quantum Number(ml) = gives the orientation(direction) of the orbital.
• 4 Spin Quantum Number(ms) = gives the direction of spin of the electron.
Allowable ranges for quantum numbers
• n (energy level) = 1 infinity• l (type of orbital = 0 n-1• ml (direction) = -l +l
• ms (spin) = -1/2 or +1/2
Determine whether each set of quantum numbers is valid or invalid:• 1) 3, 2, -1, +1/2• 2) 1, 2, 0, -1/2• 3) 4, 3, -3, +1/4• 4) 88, 67, -55, -
1/2• 5) -2, 1, -1, +1/2• 6) 1, 0, 1, -1/2• 7) 2, 0, 0, +1/2• 8) 4, 2, -3, +1/2• 9) 3, 1, 2, -1/2• 10) 4, 2, -2, +1/2
• Valid• Invalid• Invalid• Valid• Invalid• Invalid• Valid• Invalid• Invalid• Valid
Energy sublevels around an atom
energy electron
sublevels # of orbitals capacity
s 1 2
p 3 6
d 5 10
f 7 14
g* 9 18
*orbitals exist, but not used most of the time.
Orbital Notation
• Aufbau Order:• (Nucleus)1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s, 4d, 5p, 6s, 4f,
5d, 6p, 7s, 5f **This is the order in which electrons fill!!!!!You must learn the order!! Don’t worry there is always an
easier way to memorize these things. For the Aufbau Order there are 2 ways: With arrows or with the periodic table! Smartboard activate!
Electron Configurations and the Periodic Table
Figure 8.7
Electron Spin Quantum Number
Diamagnetic: NOT attracted to a magnetic field all electrons are spin paired.Paramagnetic: substance is attracted to a magnetic field. Substance has unpaired electrons.
Diamagnetic: NOT attracted to a magnetic field all electrons are spin paired.Paramagnetic: substance is attracted to a magnetic field. Substance has unpaired electrons.
Orbital Notation• Write the orbital notation for each atom:
Nitrogen, N(7 electrons)
Sodium, Na(11 e-)
Iron, Fe(__ e-)
Antimony, Sb(__ e-)
Gold, Au(__ e-)
• Write the orbital notation for each atom:
• Silver, Ag(__ e-)• Silver cations
• Aluminum cations
• Copper (I) & Copper (II) cations
• Zinc atoms & Zinc ions• Iron(II) & Iron(III) ions
Electron Configurations
Write the electron configurations for each atom:• Nitrogen, N(7 electrons)
• Sodium, Na(11 e-)
• Iron, Fe(__ e-)
• Antimony, Sb(__ e-)
• Gold, Au(__ e-)
Quantum Numbers
• Write the four quantum numbers for the last electron to fill each atom:
• Nitrogen, N(7 electrons)
• Sodium, Na(11 e-)
• Iron, Fe(__ e-)
• Antimony, Sb(__ e-)
• Gold, Au(__ e-)
Valence electrons• Give the number of valence electrons for each atom:• Nitrogen, N(7 electrons)
• Sodium, Na(11 e-)
• Iron, Fe(__ e-)
• Antimony, Sb(__ e-)
• Gold, Au(__ e-)• Silver, Ag(__ e-)• Aluminum cations• Copper (I) & Copper (II) cations• Zinc atoms & Zinc ions
Lewis Dot Structures• Give the Lewis Dot Structure for each atom:• Nitrogen, N(7 electrons)
• Sodium, Na(11 e-)
• Iron, Fe(__ e-)
• Antimony, Sb(__ e-)
• Gold, Au(__ e-)
