Chapter 6 notes Flashcard

What is wavelength (λ)?
the distance between identical points on successive waves. (units = m or nm)
What is amplitude?
the vertical distance from the midline of a wave to the peak or trough. (E = 1/λ)
What is frequency (v)?

the number of waves that pass through a particular point in 1 second (Hz = 1 cycle/s = s-1)

(s-1 = 1/s)

What is the speed of a wave (u)?
the product of the wavelength and frequency of the wave. (u = λv)
What is the numeric value of the speed of light?

C = 3.00 x108m/s

or

3.00 x1017nm/s

In the electromagnetic spectrum what is the order of radiation types from highest to lowest energy order?
Gamma rays, X rays, Ultra-violet, Infrared, Microwave, Radio waves

Calculate the wavelength (in nm) of the red light emitted by a barcode scanner that has a frequency of 4.62 x1014 Hz.

 

1Hz = 1s-1

C = λv

λ = C/v

λ = (3.00 x1017 nm/s / 4.62 x1014 s-1)

λ = 649nm

What is Planck’s quantum theory equation?

E = hv

E = energy of radiation (J)

h = Plancks constant (6.63 x10-34 J.s.)

v = frequency of radiation (s-1)

What is Plancks constant?
6.63 x10-34 J.s.
What is the equation for the photoelectric efffect?
E = hc/;
The energy required to dislodge electrons from sodium metal via the photoelectric effect is 275kJ/mol. What wavelength in nm of light has sufficient energy per photon to dislodge an electron from the surface of sodium?

The energy 275kJ/mol is for one mol of photons. To find the energy per photon, we must divide by avagadro’s number

E = (275kJ/1mol) x (1mol/6.022 x1023photon) x (1000J/1kJ)

E = 4.567 x10-19 J/photon

E = hc/λ

λ = hc/E

λ = [(6.63 x10-34- J.s.) x (3.00 x1017 nm/s)] /

(4.567 x10-19 J)

λ = 436nm

When copper is bombarded with high-energy electrons, X rays are elimited. Calculate the energy (in joules) associated with the photons if the wavelength of the X rays is 0.154nm.

E = hc/λ

E = [(6.63 x10-34 J.s.) x (3.00 x1017 nm/s)] / (.154nm)

E = 1.29 x10-15 J

What is Bohr’s equation?
E(n) = -RH(1/n2)
The change in energy when an electron undergoes a transition from one energy level to another is given by what equation?

;E = -RH [(1/nf2) – (1/ni2)]

(RH = 2.18 x10-18 J)

Calculate the wavelength (in nm) of a photon emitted by a hydrogen atom when its electron drops from the

n = 5 state to the n = 3 state.

;E = -RH [(1/nf2) – (1/ni2)]

;E = -2.18 x10-18 J [(1/32) – (1/52)]

;E = -1.55 x10-19 J

E = hc/;

; = hc/E

; = [(6.63 x10-34 J.s.) x (3.00 x1017 nm/s)] /

(1.55 x10-19 J)

; = 1280nm

What is the de Broglie equation?
; = h/mv

Calculate the wavelength of an electron traveling with a speed of 2.65 x106 m/s.

;

(mass of electron = 9.10939 x10-28 g)

(1J = 1kg m2/s2)

(h = 6.63 x10-34 J.s.)

; = (6.63 x10-34 kg m2/s2 s) / [(9.10939 x10-31 kg) x (2.65 x106 m/s)]

; = 2.74 x10-10 m

Calculate the wavelength (in nm) of a H atom (mass = 1.674 x10-27 kg) moving at a speed of 7.00m/s

;

(1J = 1kg m2/s2)

; = h/mv

; = (6.63 x10-34 kg m2/s2 s) / [(1.674 x10-27 kg) x (7.00 m/s)]

; = (5.66 x10-8 m) x (1 x109 nm/1m)

; = 56.6nm

What is the Heinsberg Uncertainty Principle?
it is impossible to know simultaneously both the position and momentum of a particle as small as an electron
If l = 0, what orbital is it in?
s orbital
If l = 1, then what orbital is it in?
p orbital
If l = 2, what orbital is it in?
d orbital
if l = 3, what orbital is it in?
f orbital

Which set of quantum numbers is permissible for; an electron in an atom?

;

a) n =1, l = 1, ml = 0, ms = +1/2

b) n = 3, l = 1, ml = 2, ms = -1/2

c) n = 2, l = 1, ml = 0, ms = +1/2

d) n = 2, l = 0, ml = 0, ms = +1

a) n =1, l = 1, ml = 0, ms = +1/2

b) n = 3, l = 1, ml = 2, ms = -1/2

c) n = 2, l = 1, ml = 0, ms = +1/2

d) n = 2, l = 0, ml = 0, ms = +1

What does paramagnetic mean?
elements and compounds that have unpaired electrons and are attached to a magnet
What does diamagnetic mean?
substances in which all electrons are paired and are slightly repelled by a magnet
What is the Pauli exclusion principle?
no two electrons in an atom can have the same four quantum numbers.

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