AP Chemsitry - Unit 1 - Atomic Structure!!

hi to anyone reading this :) i really wish i could be playing silksong or deltarune rn but no i'm studying for one oout of my 5 ap classes smh

Light Behavior

Light behaves like a wave, the medium that is waving are electric and magnetic fields

What is the relationship between frequency (ν) and wavelength (λ)?

INVERSELY proportional (high frequency = lower wavelength, low frequency = high wavelength)

Photons

the “packets” of energy that make up light, which is the smallest fundamental amount of energy

To find the amount of energy of one quantum (photon)…

you must use the equation E₀ = hv

E₀ = the energy of a photon

h = planck’s constant (proportionality constant)

v = frequency

To find the frequency/wavelength…

you must rearrange the equation, c = λv in order to find the desired value (λ = c/v, v = c/λ)

c = the speed of light, a constant
λ = wavelength (given usually in nanometers)

v = frequency (given in hertz)

Mass Spectroscopy

Used to separate varying isotopes to find an abundance of all isotopes in a given amount

• Isotope mixture ionizes

• Accelerates in paths

• ions deflect through electromagnetic field

• Collide with vacuum, detected by spectrometer

To find the average atomic mass…

Find the percentages of an isotope in a mass spectroscopy graph, multiply the isotope number by the percentage (as a decimal) and add it with the other isotopes and their percentages into calculator. result will be the average

Pauli’s exclusion principle

NO MORE than TWO electrons can occupy the SAME orbital

electrons in the same orbital MUST have OPPOSITE spins

Electrons go to the ____ energy orbital possible

LOWEST

Hund’s rule

Every orbital in a sublevel is singly occupied before any orbital is doubly occupied.

All of the electrons in singly occupied orbitals have the same spin (to maximize total spin).

What factors impact Coulumbic forces?

Distance and charge (amount)

distance (further = weak, closer = strong)

charge (zeff) - higher zeff = more difficult to remove electrons/higher attraction, lower = weaker attraction

F ∝ q₁ * q₂ / r²

Orbital energy depends on

Other electrons present —> repulsion

Rank the orbitals in from highest to lowest energy

1s (lowest), 2s, 2p, 3s, 3p 4s, 3d

Why does the 2s orbital have a greater penetration than 2p?

2s electrons can be really close to nucleus, 2p is always far out

Why do some exceptions occur electron configuration?

The 4s and 3d orbitals are very similar in energy. The pair (from the 4s orbital), will have one move to fill the empty orbitals to reach a lower energy state and gain stability

Example: Cr would be [Ar] 4s1 3d5, since the electron that was originally in the 4s orbital would move to the 3d orbital in order to fill the empty spot in the 3d orbital, allowing for the subshell to be half filled

Paramagnetism

Unpaired electrons —> HAVE magnetic properties (the more unpaired electrons, the stronger the magnetic properties)

diamagnetism

paired elelctrons —> NO MAGNETIC PROPERTIES

Which groups contain diamagnetic elements

2, 12, and 18 (filled s, half filled p, fully filled s and p)

When forming cations (LOSING electrons)

last electrons in are the first ones out (valence)

When forming anions (GAINING electrons)

add to the lowest energy orbital available

Transition elements lose ___ electrons before ___ electrons

s orbital, d orbital.

Why? - s and d orbitals are very similar in energy, but the s level is higher, so it wants to go to lower energy

Isoelectronic

same electron configuration, different identity (Ca+2 and Cl-)

For transition 2+ or +3 ions…

there is no 4s orbital, they immediately go to the 3d orbital

the 3+ ions are easy to form since the 6th electron is very easy to loose (more stable if all spaces are half filled) and allows for lower state of energy

What is the principal interaction impacting ionization energy?

Coulombic attraction!

Does ionization energy only include the electron’s interaction with the nucleus?

No, also has to do with other electrons and repulsive forces

First ionization energy

the electron removed from an ion

Second ionization energy

Electrons become more difficult to remove since it becomes smaller, repulsive forces weaken but attraction remains stagment, therefore making electrons harder to remove

Zeff equation

Zeff = Z -S

Zeff = effective nuclear charge

Z = all electrons

S = core electrons

For valence electrons, the repulsion of each core electron is ________ to the attraction of each proton in the nucleus. They ___ each other out

equal, each