Flashcards in 6 - electronic structure Deck (21):
What is a shell?
An energy level which electrons are arranged in
The further away the shell from the nucleus, the higher the energy level
What is the other term for shells and how is it used?
The principal quantum number
The fourth shell has a principal quantum number of n = 4
A region within an atom which can hold up to 2 electrons which will have opposite spins
What is spin?
The direction in which an electron spins
An electron can spin up or spin down
when an electron is al
Why do orbitals have 2 electrons of opposite spin?
Oppositely spinning electrons pair up naturally in order to reduce repulsion
How do you draw an orbital as a diagram?
A pair of electrons in an orbital:
A square representing the orbital
One up arrow and then a down arrow to the right of it to represent the 2 opposite spin electrons
-fill up spins first, when only 1 electron it has an up spin
What are the 4 orbital types?
Describe an S-orbital and how it fits into electronic structure
It has a spherical shape
Every shell has a single S-orbital
S-orbitals provide space for 2 electrons in each shell
Describe a P-orbital and how it fits into electronic structure
It has a dumbbell shape (3D)
There is one P-orbital per axis per shell
So there is 3 P-orbitals per shell (X, Y and Z axis)
There is one set of 3 P-orbitals in every shell after n = 2
A set of P-orbitals provides space for 6 electrons (3 spin pairs)
Describe how D-orbitals fit into electronic structure
There are 5 D-orbitals per shell meaning they provide space for 10 electrons per shell
There is one set of 5 D-orbitals in every shell after n = 3
7 orbitals per shell
Space for 14 electrons per shell
One set of 7 F-orbitals per shell after n = 4
How do you find the number of electrons in a shell from the principal quantum number?
Take the principal quantum number
That's the number of electrons in that shell
What is a sub-shell?
A group of the same type of orbitals within a shell
E.g the D sub-shell is the 5 sets of orbitals in one shell
How do the electrons fill the different orbitals and shells?
They go into the lowest shell possible
They go into the smallest sub-shell possible (S first and F last)
They spread out as much as possible between the different orbitals in a sub-shell
How do you write the electronic configuration of an atom?
The principal quantum number then the orbital type then the number of electrons in that sub-shell is superscripted
Then do the same for the next sub-shell
You write the lowest energy sub-shell first and the highest last
E.g If there is 7 electrons:
There is 2 electrons in the n = 1 S orbital
Written as: 1s^2
There is 2 electrons in the n = 2 S orbital
Written as: 2s^2
There is 3 electrons in the n=2 P orbital
Written as 2p^3
The entire electronic configuration is:
1s^2 2s^2 2p^3
How would you abbreviate a noble gas electronic configuration?
Just write the symbol of the noble gas in brackets
Write the electronic configuration of nickel (28 electrons)
why is the order strange?
1s^2 2s^2 2p^6 3s^2 3p^6 4s^2 3d^8
or [Ar] 4s^2 3d^8
4s has a lower energy level than 3d so 4s is actually filled up before 3d is
Describe the process of calculating the electronic configuration of an ion
If the charge is 2-, add 2 electrons
If the charge is +, take away an electron
Use this number of electrons to calculate the electronic configuration
Calculate the electronic configuration of Li +
The proton number of lithium is 3
3 electrons in lithium atom
Charge is +
2 electrons in Li +
So the electronic configuration is 1s^2
Abbreviated to (He)
What do you have to do to calculate the configuration of the ion of a transition metal?
Calculate the configuration of the base atom first
Take away the electrons from the configuration to make the ion after
Take away electrons from the outer shell first
E.g (Ar) 4s^2 3d^1
You need to take 2 electrons
You take them from 4s because of the nature of reactions
So the ion's configuration is (Ar) 3d^1