1.2 Quantum mechanics & electron arrangement

What is the principle quantum number (n)

The principle quantum number tells you which ring/energy level the electron you are examining is found within

How does the principle quantum number allow us to know the max number of electrons within a specific energy level

The maximum number of electrons that can be found in a specific energy level is = to 2n² where n is the principle quantum number associated with that energy level

what are sublevels of energy levels and how many are there per energy level

Energy levels can be further broken down into distinct sublevels labeled s, p, d, and f,

There are (n-1) sublevels per energy level where n is the principle quantum number associated with that energy level

How do the energies of electrons within the same sublevel compare

electrons within the same sublevel have the same amount of energy, but have different energies compared to electrons within a different sublevel

what is the angular momentum quantum number (l)

the angular momentum quantum number (designated by the l variable) is a number associated with the sublevel the electron you are examining is currently on. l = 0 for s, 1 for p, 2 for d, and 3 for f.

what did werner heisenberg prove

Heisenberg proved that it was impossible to know the instantaneous position and velocity of an electron beyond a certain measure of precision.

• this led to the development of the idea of probability instead of certainty

what is an orbital

an orbital is a 3D region of space where the probability of finding an electron is high

what is the magnetic quantum number (ml)

Every sublevel has a specific amount of orbitals it can contain within it. the ml value indicates which orbital the electron you are examining most likely resides in, and the direction of the orbital

How to know how many orbitals are within a specific sublevel

the number of ml values indicates the number independent orbitals that are possible for that orbital. The formula for number of ml values is (-l,…,+l) where l is the angular momentum quantum number

How many electrons can be found within a singular orbital and how are they spinning

a singular orbital can hold a maximum of 2 electrons and both have to be spinning in opposite directions denoted by their spin quantum number (ms)

what are the two possible values for spin quantum number (ms)

• +1/2

• -1/2

• clockwise is +, counter-clockwise is -

What is quantum mechanics

quantum mechanics is the study of the probability of finding an electron in a region of space around the nucleus.

• its calculations are based on the electron as a particle, with its motion expressed as a wave

what is the shape of an s orbital

the s sublevel (sigma) contains only one orbital and thus only two electrons,

• the shape of the orbital is a spherical region

what is the shape of a P orbital

The P sublevel contains three orbitals, with a total of 6 electrons

• an orbital has the shape of two lobes along a specific axis, every orbital follows a different axis

• the three orbitals are : Px, Py, and Pz as the subscript indicates the specific axis they are situated along

how many orbitals and total electrons does the D sublevel hold

the D sublevel holds 5 orbitals totalling 10 electrons

how many orbitals and total electrons does the F sublevel hold

the F sublevel holds 7 orbitals totaling 14 electrons

How do these orbitals fit together on a singular atom

starting from the inner most energy levels, sublevels are added as required until all electrons are added

• as levels and sublevels are added, they continue to build on what is already present

what are the three rules for electron organization

• Aufbau principle

• Pauli exclusion principle

• Hunds rule

What is the Aufbau principle

The aufbau principle states that orbitals and their respective levels have different amounts of energies associated with them.

Electrons from normal “ground state” atoms will occupy the lowest energy levels first then subsequently fill the next lowest level until all electrons are accounted for

How to know the energy level of a sublevel and the order of which electrons will fill them

electrons fill subshells in order of increasing (n + l) value where n is the principle quantum number and l is the angular momentum quantum number.

If two subshells have the same (n + l) value, the one with the lower n value is filled first

what is electron configuration and how is it found for electrons with low number of electrons

electron configuration is a numerical representation of the arrangement of electrons within an atom, demonstrating which electrons most likely reside in which orbitals.

this can be found by filling orbitals in order of the aufbau ladder or memorising the first 7 values of the aufbau ladder until all electrons are accounted for

• 1s, 2s, 2p, 3s, 3p, 4s, 3d …

what is the pauli exclusion principle

the pauli exclusion principle states that all orbitals hold a maximum of 2 electrons and they must be spinning in opposite directions

what is Hunds rule

Hunds rule states that when an atom contains more than one orbital of equal energies but does not have the number of electrons necessary to fill them all up, electrons will be given to each before doubling can occur.

Paramagnetic vs Diamagnetic orbitals

Paramagnetic orbitals are orbitals with 1 electron and they are affected by magnetic fields

Diamagnetic orbitals are orbitals with 2 electrons (full) and they are not affected by magnetic fields