Unit 1: electronic structured and periodic properties of elements

What is 𝛎 (nu)

symbol for frequency

does electromagnetic radiation travel at different speeds?

no! all electromagnetic radiation travels at 3 × 10^8 m/s or the speed of light.

whats the speed of light

3 × 10^8 m/s = C

3 characteristics of waves 

• lengths ( λ lambda)

• Amp (height)

• Frequency ( 𝛎 Nu )

how is wavelength and frequency related?

C = λν, where c is the speed of light

constructive interference

when the amps of two waves combine- making extra stretched wave

destructive interference

when tops and bottoms of 2 seperate waves cancel out leaving a line

Planck’s theory

that energy can only be absorbed or released from atoms in certain amounts - basically energy releases in these little bursts called quanta

Quantum def:

Smallest amount of energy that can be emitted/absorbed as electromagnetic radiation

what is Plancks constant ( h)

= 6.626 × 10 ^ -34 js

relationship between energy and frequency

E = hv

energy = plancks Constant x Nu

this describes that energy comes in little bursts proportional to its frequency.

what does the photoelectric effect describe?

• when the surface of a metal is hit by electromagnetic radiation it ejects electrons 

• however in order for this to happen the photons in the electromagnetic waves must have enough energy 

• based on the derived equation 

E = h(c/λ) ,

• the shorter wavelength something has the more energy it will have - therefore the more electrons it will eject

• the maximum wavelength for emitting electrons is 550 nm ( which is equivalent to green light) 

Bohr Model 3 main ideas

electrons are confined to specific energy states ( orbits)

1)only orbits of specific radii are permitted for electrons in an atom( electrons must stick to that radii??)

2) an electron in a permitted orbit has a specific energy

3)energy is emitted or absorbed by an electron as it moves from one energy state to another

what happens as electrons move between energy states?

• as electrons move to lower energy states light is emitted

• as electrons move up energy states light is absorbed

Matter Waves

De Brogile’s theory that if light can have material properties- matter should exhibit wave properties 

basically matter has waves - for most objects however the wavelength they emit is so small its pointless 

leading to this eq: λ= h/mv 

where h is plancks constant ( I assume)

m is mass, and v is velocity 

Uncertainty principle

Since everything ( materials and light) have both material and wave properties it sets a limit on how precisely we can know the location and momentum of an object

TLDR : cant find the momentum and location of an object at the same time ( measuring one will interfere with the other ) - obv this applies to subatomic particles not like everyday objects

formula involving uncertainty principle

(uncertainty of x )(uncertainty of mv) ≥ h/4pi

what is Ψ?

Ψ wave function ( symbol being psi) describes the behaviour of a quantum mechanical object ( too advanced for me but what is relevant→) Ψ² gives electron density - a region of high electron density = high probability of finding an electron

basically there are orbitals ( not fixed orbits) where electrons are most likely to be found

What do the three quantum numbers tell u ( theory based)

the three quantum numbers tell you where the orbital is , what shape it is and how its oriented. 

What is the principle quantum number n?

n is a positive integer - that describes the main energy lvl( or shell), basically how far the orbital is to the nucleaus

n also correlates to the amount of sub shells that are in that energy lvl 

a greater n value correlates to being in a shell further away from the electron nucleaus and therefore higher in energy

What is the angular momentum quantum number 𝓁?

𝓁 tells u the shape of the orbital.

maximum possible value for 𝓁 is n -1 ( 𝓁 can be less than the number quite frequently tho)

and each 𝓁 value correlates to a letter that describes the shape of the orbital. 

𝓁: 0 1 2 3 

   s p d f 

What is the magnetic quantum number M (subscript 𝓁) ?

correlates to one orbital with a unique orientation is space ( each orbital with a different orientation is a seperate orbital) 

maximum value depends on 𝓁 ( thats why 𝓁 is in subscript) , m𝓁 can take on values from -𝓁 to 𝓁. So basically the greater the 𝓁 value, the more complex the shape and the more possible orientations available ( or possible m𝓁 values)

how can u figure out fuckass number of nodes/node types?

total nodes = n-1

however within the total nodes there are two types, angular and radial

angular nodes define the shape - ( having one sphere, vs 2 , vs a clover shape) and the amount of angular nodes is determined by 𝓁

radial nodes are whatever is left over: basically (n-1) - 𝓁 = amount of radial nodes, since in many cases 𝓁 < n - 1

the radial nodes appear in a certain radius from the nucleus, cutting the orbital up into rings kinda

• overall shape tho ( like amount of circles around the nucleaus ) is determined by the angular nodes, then the leftover radial nodes cut the orbital up into rings…

how can u tell where nodes are on diagram?

cause the color of the orbital changes as it passes thru a node ( goes from neg to pos if nodes are 0) color of orbital changes as sign changes

whats the funky d orbital? 

dz² , its a nodal cone 

4th quantum number? M (subscript S)

spin magnetic quantum number - shows wether electron is spin up or spin down values include +1/2 for spin up and -1/2 for spin down.

Pauli’s exclusion principle

no 2 electrons can have the same set of 4 quantum numbers, therefore if they exist in the same orientiaon (m𝓁) one has to be spin up and one has to be spin down

• an example of Paulis exclusion principle would be 3 elections in one box ( or 3 elections in the same sub shell orientation?)

Hunds Rule:

for orbitals of the same energy ( n), the lowest energy is attained when the number of electrons with the same spin is maximized. Filling all the spin ups first will help with stability - minimizes electron-electron repulsion.

What orbital does D start with?

D starts with 3d, even though it’s in the 4 line.

what orbital does f start with?

f starts with orbital 4 even though its in line 6

2 Anomaly electron configurations ( memorize)

• Cr [ Ar ] 4s^1 3d^5 ( all shells are half filled for stability)

• Cu [ Ar ] 4s^1 3d^10 ( all shells are again half filled for stability)

Aufbau Principles 

1) lower energy orbitals (n) fill with electrons first’

2) Any orbital can hold up to 2 electrons. 2 electrons in the same orbital must have opposite spins - Pauli exclusion principle 

3)if 2 or more orbitals with the same energy are available, one electron fills each shell until are all half filled ( improves stability ) - Hands Rule

what is orbital digram? ( notation)

what is sub shell notation?

draw different orientations for d orbital

electron configuration of cations and anions?