Atomic Theory Chapter 12 Flashcards
Wavelength(w)
Distance between the adjacent crest of a wave (in m )
Frequency(v)
The number of crests passing through a given point per second (in Hz or s^-1)
Speed of light (c)
speed of the movement in a given crest
Constant value is: 2.988 x10^8 m/s
Formula for Sped of light
c= v(w)
Amplitude
Max height of the wave above centerline
Constructive interference
When a crest of a wave meets another crest of another wave the amplitude of the waves add together.
Destructive interference
a crest of a wave meets a trough of another wave, the two waves cancel each other out
Black body radiation Part 1
All non-reflective objects (black-bodies ) emit light (black body radiation).
- Black body room temperature appears black as most of the energy it emits is Infared
- A heated metal emits visible light
- Temp becomes higher, the color of emitted light shifts from red to blue
Photons
They are a stream of particles that light is made up of and has energy
Plank’s equation
E photon = hv = hc/ w
Plank’s constant
h = 6.626 x 10^-34 Js
Law of conservation of Energy
Ei + hv = Ef
Electron circular orbits formula
En = - Z^2 (RH)/ n^2
Rh constant
2.179 x 10^-18
Z
atomic number
Law of conservation of energy
Eph= hv= Ef-Ei
Black body radiation part 2
- Spectrum of black body radiation is peaked at a characteristic frequency that shifts to shorter wavelength with increasing temperature
Higher temp = shorter wavelength - Classical theory falsely predicts that intensity would increase indefinitely with decreasing wavelength
Energy of light with frequency v
Is quantized because energy must be an integer multiple of the photon energy.
Different measurements of wavelength least to greatest
pm<nm<mm<m of wavelength
Electromagnetic radiation
Eletric and magnetic fields propagate as waves through a vacuum or through a medium.
why is energy of light with frequency(v) is quantized
Energy must be the integer multiples of the photon energy.
Emission
is the way in which excited atoms emit energy as photons to relax to lower energy levels.
emission spectra of atoms
discontinuous
absorption spectra of atoms are
discontinuous
Photoelectric effect
When more light energy is directed towards a black body object the more electrons are removed to only a certain threshold.
Wave-particle duality Du Brogoli
Light (or anything else) can act as both as a wave and as a particle.
Wavelength of the of material particle is inversely proportional to its momentum (and its velocity.
Formula λ= h (Js) /mu (m/s)
Ionization Energy of hydrogen
When photon energy is absorbed by a hydrogen atom is just enough to remove an electron from the ground state (n=1), the atom is ionized
H —> H^+ (+) e^-
Isolated stationary electron
When the final energy state of an electron reaches zero Ef=0
Ionization energy formula
Energy of photon being absorbed.
Formula hv= Ef-Ei= 0 - E1 = RH
what is u?
the speed of the particle
Heisenberg’s uncertainty principle
There is a fundamental limit to which with the position of the particle (x) and its momentum (p) can be measured simultaneously.
Heisenberg’s uncertainty formula
∆𝑥: uncertainty of measured values of x
∆𝑝: uncertainty of measured values of p
∆𝑝= m ∆u
∆x∆u> h/4(pi)m
∆x∆𝑝>h/4(pi)
Product: ∆x ∆u decreases with increasing mass
Heisenberg’s uncertainty principal part 2
The more you become more precise in measuring the position (x) more precisely you lose position of the momentum.
∆𝑥 —-> 0
∆𝑝 —-> inf
inverse happens when you try preciseluy measure the momentum.
Wave function 𝜓(x)
describes a particle exhibiting wavelike properties (quantum particles)
Energies (En)
n= (1,2,3,… )
𝜓n^2 Probability density
the probability of finding the particle at a given position (x) and is always positive
Quantum mechanics relasonship
Quantum # (Energy) (Wave f Prob g/ml
n= 1 E1 𝜓1(x) 𝜓1^2(x)
n =2 E2 𝜓2(x) 𝜓2^2(x)
n= 3 E3 𝜓3(x) 𝜓3^2(x)
Wave functions
𝜓n (x)= square root(2/L) sin (n(pi)/L x)
En = (n^2h^2/ 8mL^2) where n= 1,2,3….
2
𝜓n is a sine function: Wavelength = 2L/n
Particle in a box- Particle densities
When solving for wave function = 2L/n
When solving for n value # of nodes = n-1
Probability density becomes zero at nodes of the wave function
# of nodes = n-1
r
distance from the nuclues
𝜃, 𝜙
orientation
wave function of an electron be factorized into the product of two functions.
R(r) is called the radial wave function
Y(𝜃, 𝜑) called angular wave function
Principle Quantum number
quantam number represents the overall energy of each orbital. Energy level increases as its distances from the nucleus increases.
Angular Momentum quantum number
l= 0,1,2,…, (n-1) orbitals with the same l tend to be in the same subshell.
When finding range just remember the n-1 at the end, and there is a given n value.
Finding the total amount of orbitals you need to square amount of n given = n^2
Magnetic Quantum numbers
m𝑙 = -l, -l+1, …,0,…, l-1, 1 (-3,-2,-1,0,1,2,3)
Determining the range is with given value of l , then simply plug those in -l and +l. Also when finding total number of orbitals = 2l+1
Remebers that orbitals in the same shell have…
the same energy
Subshells
a subdivision of electron shells that are separated by electron orbitals. They are s,p,d, and f
s has 2 max electrons
p has 6 max electrons
d has 10 max electrons
f has 14 max electrons
The l value increases by one
ml values
determined by the value given l value from -l to +l. Ex: 3d has ml = -2, -1, 0, 1, 2 because l value is 2 at d
paramagnetic
in examining electron configuration there is unpaired electrons they are attracted to magnetic field
magnetic properties
in electron configuration there is paired electrons and they are slightly repelled in magnetic field
s-block
1A, 2A, and 8A (holds two electrons)
p-block
3A-8A (excluding He) (holds 6 electrons
d-block
3b-8b and 1B-2B (holds 10 electrons)
f-block
lanthanides and actinides (Bottom 2) (holds 14 electrons)
When writing electron configuration
the exponents assigned to the s,p,d, and f values coorelate to the position they are in the periodic table from left to right. Ex: H = 1s and He = 1s^2
Ionization trend in the periodic table
increases the further you move right and up the periodic table
Spherical nodes
they all start at zero but increase by 1 with every increase in the value of node
Angular nodes
they are determined by the l formula of a orbital system: s, p, d, and f. Which results in the formula n> or equal to l+1
Number of orbitals given within a sign is by n = n^2
s = 1
p= 4
d = 9
4 = 16
possible values of ms is
always 1/2 or -1/2
Radius trend in a periodic table
from the left and down
Trend in atomic radius in the periodic table
From left and down
conversion of cal to joules
1 cal = 4.18 joules
zero-point energy
vibrational energy of a molecule retain even at the absolute zero of temp. It is a minimal non-zero energy of a quantum mechanical system.
An atomic orbital represents.
the region of high probability for an electron around the nucleus of an atom
Paulie exclusion principle
States that two or more identical particles with half-integer spins cannot occupy simultaneously occupy the same quantum space.
Rydberg Principle
calculates the wavelength of spectral line in many chemical elements. It is a generalization of Balmer series
Balmer series
1/wavelength = Rh (1/nf^2 -1/ni^2
Hund’s rule
describes arrangement of electrons in their configurations. Such as in the p block are available, electrons will first occupy separate orbitals with parallel spins.
Aufbau principle
ground state of an atom or ion, electrons fill subshells of the lowest available energy then they fill subshells to the highest energy. Electrons also attempt to be as far as apart of each other as possible. Chromium and Copper in the 4th row are exceptions to principle.
Formula for finding wave length or electron by itself
Wave length = h/p = h/mv
Mass of electron constant
9.109 x 10^-31
