atomic theory and structure 1-4

fuh naw

wavelength variable & units

variable: λ

units: m, nm (10^-9m), Å (angstrom 10^-10m)

frequency variable and units

variable: 𝜈

units: hz, sec^-1, cycles/sec

higher frequencies lead to

high nrg

unit c

speed of light 

2.998 × 10^8 m/s

relationship between wavelength, frequency and speed of light

λ * 𝜈 = c

order of light

LOW → HIGH

gamma, xray, UV, visible, IR, micro, radio

low energy → λ & 𝜈

long wavelength, low frequency, low nrg & vice versa

gamma 

10^-12

xray

10^-10

ultraviolet

10^-8

visible

4×10^-7 → 7×10^-7

purple → red

400 nm → 700 nm

infared

10^-4

microwave

10^-2

radio

10²

Newton’s conclusion

light is a particle

pattern seen from the double slit experiment

light is a wave that can interfere with itself

Young’s conclusion

light is a wave

constructive interference

destructive interference

name of “packets” of energy

quanta

Planck's formula & constant

Formula: E = h𝜈 or ΔE = nh𝜈 

h (constant) = 6.626 × 10^-34 Js

on formula sheet

energy of a wavelength of purple light

400 nm (4×10^-7) → (h*c)/𝜈

planck’s conclusion

light (& nrg) is a quanta

what happens when you shoot lower wavelengths at sodium metal

electrons are removed with higher velocity (?)

particles of light (einstein)

photons

when a high nrg photon hits an electron, what happens to the ecess nrg after the electron has left the metal?

excess nrg is converted to KE so the electron moves faster

ionization effect

left → right nrg increases making it harder to remove electrons

einstein’s conclusion

light is a particle

De Broglie’s equation

λ = h/p = h/mv

p = momentum

m = kg

v = m/s

NOT on constant sheet

radius of the nucleus

10^-15 m

electrons don’t exist in the nucleus

bond distance

10^-10 m

de Broglie’s conclusion of matter

matter is a wave

Rydberg equation

1/λ = R(1/n²₁ - 1/n²₂)

Rydberg constant (R)

1.096776×10^7 m^-1

What is the value of n₁ for the Balmer & Rydberg equations

n₁ = 2

Bohr Laws (?)

1. electrons can only exist in certain states of levels. each is associated with a value of “n”

2. the states with higher n are higher in nrg

3. an electron can be promoted to a higher state by absorbing a photon whose energy equals the difference between the two states

4. an electron dropping to a lower state emits a photon whose energy equals the difference between the two states

energy of an electron

-2.178×10^-18 J * (Z²/n²)

Z = nuclear charge (atomic #)

simplified Balmer formula (Bohr)

ΔE = h𝜈 = -2.178×10^-18J(Z²/n²_f - Z²/n²_f)

how many nrg levels are in an atom

infinite

When an electron is at the highest possible nrg level, or the highest value of n, what is its nrg? what does this mean for the electron

E = 0; the electron has been removed from the atom