Lecture 5/6-The Electronic Configuration Of The Atom Flashcards
Where are e- in an atom?
In stable energy levels
What does the absorbtion of a photon of light do?
Allow the e- to jump to a higher level
What does the jumping down of an e- to a lower level do?
Emits a photon of light
If you measure the energy of the photon that has jumped up + down, what will you find?
The energy difference between levels (they are not evenly spaced)
What is 1st ionisation energies?
The energy required to remove 1 mole of e- from 1 mole of gaseous atoms to form one mole of positive ions
Why are ionization energies positive?
Energy must be put into the system to pull the negative e- away from the positive protons
Why does higher nuclear charge have a higher ionization energy?
Because there is a greater pull of the nucleus on the e-
What is e- affinity?
The energy required to add 1 mole of e- to 1 mole of gaseous atoms to form 1 mole of gaseous negative ions
Cl-(g) + e- —> Cl-(g)
E- affintiy
The more negative the e- affinity the ……
more STABLE the negative ion
Why is the 2nd e- affinity positive?
Because energy needs to be put in to add e- to a negative ion
Atomic size trends
Increases down a group
Decreases across a period
1st Ionization energy trends
Decrease down the group
Increase across a period
1st E- affinity trends
Less negative down a group
More negative across a period
What are orbitals?
Regions in space where there’s a 95% probability finding a particular e-
What does the quantum number n indicate
- The distance of an e- from the nucleus
- The energy of an e-
- Number of e- a shell can hold
The higher the quantum number n the?
The further away from the nucleus the e- is
Higher energy e- are less tightly held and so….
more easily removed (higher n)
n can have how many electrons?
2n^2
How many e- can: K shell L shell M shell N shell have?
K shell n=1 ,so e- = 2
L shell n=2 ,so e-=8
M shell n=3 ,so e-=18
N sheel n=4 ,so e-=32
What is a subshell?
A group of orbitals with the same energy
The value of l depends on what quantum number?
n
What values can l have?
From 0 to n-1
What are spin quantum numbers?
The clock-wise + anticlockwise spinning of e- produces opposite magnetic fields
Why is Gd3+ used for medical imaging?
The 7 unpaired electrons have the same spin (½) but a much smaller size than protons so it can be magnetized @RT
What other ions/elements can be used for medical imaging?
Iron , nickel , cobalt
What does the Azimuthal quantum number indicate?
The subshell an e- is in
If the value of l is: -0 -1 -2 -3 what subshell is it in?
0=s
1=p
2=d
3=f
Does the energy of the subshell increase with increasing of l?
YES
What is the maximum number of e- a given subshell can hold?
2(2l+1)
If l is 0=s 1=p 2=d 3 =f then how many e- can it hold
s=2
p=6
d=10
f=14
What is the shape of the: s orbital p orbital d orbital f orbital
s = spherical p = dumbbell d = more complex f = still more complex
What do magnetic quantum numbers represent ? (m/m1)
The orbitals in a given subshell
What do magnetic quantum numbers indicate?
The direction of a particular orbital relative to the magnetic field/axes
Does magnetic quantum numbers indicate energy?
NO
m can have an integral value of what?
-1 through 0 to +1
For a given value of l, total number of m value is what?
(2l+1)
Heisenberg’s uncertainty principle
You cannot determine the position + momentum of an e- at the same time
Aufbau principle
E- enter the lowest available energy level 1st
Hund’s rule of max multiplicity
When in orbitals of equal energy , e- will try to remain unpaired (minimises repulsion between like charges , so the system is more stable)
Pauli exclusion principle
No 2 e- can have the same 4 quantum numbers
-Only 2 e- can go in each orbital , if they’re of opposite spin
What are the special cases / exceptions?
Chromium = 4s1 3d5 Copper = 4s1 3d10
A large jump between successive ionisation energy indicates what?
A change in energy level from which the e- has been removed
