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Question 1

Electron Configurations

Answer 1

n - Principal Quantum Number
describes the energy of the electron n = 1, 2, 3…

l - Angular Momentum Quantum Number
describes the shape of the orbital l = 0, …, n-1

m(l) - Magnetic Quantum Number
describes the orientation of the orbital ml = l, (l-1), .. 0, …, -l

m(s) Spin Quantum Number
describes the spin of the electron ms = +½, -½

Question 2

Atomic orbitals: shell

Answer 2

all orbitals derived with the same value of quantum number n.

Question 3

Atomic orbitals: sub-shell

Answer 3

all orbitals in a given shell derived with the same value of quantum number l.

Question 4

Orbitals

Answer 4

non-uniform distribution of the electron matter over space around the nucleus.

Question 5

Electron density

Answer 5

measured by the value of ψ^2

The shape of an orbital is defined by a surface connecting points of equal electron density.

Plots of orbitals^2 (or more accurately 4πr2ψ^2) vs distance from the nucleus, r, can be very helpful to better understand the distribution of electrons in an atom.

Question 6

ψ^2

Answer 6

a measure of probability of finding the electron at any point in space (electron density)

r90 indicates the radius of a sphere containing 90% of the electron density.

These boundary surfaces are usually drawn when we want to show an orbital

Question 7

s orbitals

Answer 7

spherically symmetrical. The larger the quantum number n the larger the radius r(90) of the isodensity surface

• s orbitals are not solid spheres, nor candy egg shells, but more ‘onion’ like, with the number of concentric ‘nodes’ dispersed through the probability density increasing with n

Question 8

p orbitals

Answer 8

‘dumbell’ shaped. The larger the quantum number n the larger the radius r(90) of the isodensity surface

• p orbitals also feature a series of nodes which increase with n
• p orbitals exist in three different orientations in space (l = 1; ml = -1, 0, +1)

Question 9

d orbitals

Answer 9

more complex multi-lobe shaped. The larger the quantum number ‘n’ the larger the radius r90 of the isodensity surface

• d orbitals also feature a series of nodes which increase with n
• d orbitals exist in five different orientations in space (l = 2; ml =-2, -1, 0, +1, +2)