Flashcards in L5 & 6: The Electronic Configuration of the Atom Deck (50):
What is 'Heisenberg's uncertainty principle'?
You can never know both the position and the momentum of an electron at the same time
What is 'the Aufbau principle'?
Electrons enter the lowest available energy level first
What is 'Hund's rule of maximum multiplicity'?
When in orbitals of equal energy, electrons will try to remain unpaired.
Bus rule: When you get on a bus, you go for the vacant row before sitting next to another person
What is the 'Pauli exclusion principle'?
No two electrons can have the same four quantum numbers. Only 2 electrons can go in each orbital, providing they are of opposite spin.
How can an electron jump up to a higher energy level?
Absorbing a photon of light
How can an electron descend an energy level?
Emitting a photon of light
How can you determine the amount of energy between energy levels?
Measure the energy of the photon emitted by a descending electron
What is 'a measure of the amount of energy needed to remove electrons from atoms or ions'?
Define 'first ionisation energy'
The energy required to remove one mole of electrons from one mole of gaseous atoms to form one mole of gaseous positive ions
Are ionisation energies positive or negative? Why?
Positive - to overcome the attraction between an electron and the protons in the nucleus, energy must be added to the system.
True or false: lower nuclear charges result in higher ionisation energies
False. Higher nuclear charges result in higher ionisation energies.
The greater the pull of the nucleus, the harder it is to pull an electron away. Therefore, more energy is required.
Define 'electron affinity'
The amount of energy needed to add electrons to atoms or ions
What is 'the energy needed to add one mole of electrons to one mole of gaseous atoms to form one mole of gaseous negative ions'?
First electron affinity
Are electron affinities positive or negative?
Negative. Energy is released when electrons are added to an atom
True or false: The more negative the electron affinity, the more stable the negative ion that is formed
True or false: Atomic size increases along a period and down a group
False. Atomic size decreases along a period; increases down a group
True or false: First ionisation energy increases across a period
True or false: First ionisation energy increases down a group
False. First ionisation energy decreases down a group
True or false: Patterns of first ionisation energy are opposite to the patterns of atomic size (i.e. as atomic size increases, 1st I.E. decreases, and vice versa)
Fill in the gaps:
First electron affinity becomes _____(1)______ negative across a period, and _____(2)_____ negative down a group.
What are the three most important factors to take into account when explaining trends in the periodic table?
3) Atomic size
What are the four quantum numbers required to specify the character of an electron?
1) Principal (n)
2) Azimuthal or subsidiary (l)
3) Magnetic (m)
4) Spin (s)
What three things can be determined by the principal quantum number (n)?
1) Distance of electron from the nucleus - higher n = further from nucleus
2) Energy of electron - higher n = higher energy e-
3) Number of electrons a shell can hold - 2n^2
How many electrons can L-shell hold?
L-shell n = 2
2n^2 = 2 x (2^2) = 2 x 4 = 8
How many electrons can N-shell hold?
N-shell n = 4
2n^2 = 2 x (4^2) = 2 x 16 = 32
What is the rule for allowed values of n?
n = value greater than 0
What do the azimuthal or subsidiary values correlate with?
l = 0 = s-subshell
l = 1 = p-subshell
l = 2 = d-subshell
l = 3 = f-subshell
What is the rule for allowed values of l?
l = 0 to (n-1)
If n = 3, what are the allowed values of l?
l = 0, 1, 2
If n = 1, what are the allowed values of l?
l = 0
How many electrons can a given subshell hold?
Calculate using formula 2(2l+1)
What is the maximum number of electrons that can be held in the d subshell?
2(2x2+1) = 4+1 = 5
5 x 2 = 10
Which subshell is spherical?
What shape is the orbital represented by l=2?
D) Most complex
l=2 is the d-subshell, which is a complex shape.
True or false: Putting the n value and the l value together (nl) gives you the specific subshell number
E.g. Shell M, n=3, l=0 is the 3s subshell; l=1 is the 3p subshell....etc
What is the rule for allowed values of m?
m = value ranging from -l to +l, including 0
If l=0, what are the allowed values of m?
m = 0
If l=2, what are the allowed values of m?
m = -2, -1, 0, +1, +2
If n = 3, what is the maximum allowed value of m?
Max value of l=2, therefore the max value of m = +2
What does the spin quantum number show?
Whether the electron is spinning clockwise (+1/2) or anticlockwise (-1/2)
If there are two electrons in the same orbital, what will their s values be?
One will be +1/2 and the other will be -1/2
What is the rule for allowed values of s?
s = -1/2 or +1/2
Which principle states 'you cannot determine the position and momentum of an electron at the same time'?
Heisenberg's Uncertainty Principle
Which principle states 'electrons enter the lowest available energy level first'?
The Aufbau Principle
Which principle states 'when in orbitals of equal energy, electrons will try to remain unpaired'?
Hund's Rule of Maximum Multiplicity
Which principle states 'No two electrons can have the same four quantum numbers'?
Pauli Exclusion Principle
True or false: In transition metals, electrons in the 4s orbital are removed before any electrons in the 3d orbitals
While analysing an element's successive ionisation energies you notice that there are some large jumps that are significantly larger the others. What does this tell you?
A large jump in ionisation energy indicates a change in energy level
What is different about the orbital filling of chromium and copper?
When the d-orbital is almost full, or almost half full, it can steal an electron from the preceding s-orbital