Atomic Structure - Atomic Orbitals, Electron Configuration Flashcards
describe what happens as we move further from the nucleus
As we move further from the nucleus, the energy of the shells increases
where do electrons exist
electrons exist in electron shells
electron shells = main energy levels
electron shells = main energy levels
What is each shell given
What is this called
Each shell is given a number
This is called the principal quantum number or ‘n’
state the principal quantum numbers of the first shell, second shell and third shell and fourth shell
First shell has a principal quantum number of 1 (n=1)
Second shell - n=2
third shell - n = 3
fourth shell, n = 4
Calculate the maximum number of electrons that each shell can hold
maximum number of electrons = 2n^2
n=1
first shell - max 2 electrons in first shell
second shell - max 8 electrons in second shell
third shell - max 18 electrons in third shell
fourth shell - max 32 electrons in fourth shell
Where are electrons in a shell found
Electrons in a shell are found in regions called atomic orbitals
What is an atomic orbital
An atomic orbital is a region around the nucleus that can hold up to two electrons with opposite spins
types of spin electrons can have
Electrons can either have an up spin or a down spin
What must two electrons in he same orbital have
When we have two electrons in the same orbital, these two electrons must have opposite spins
(cant have two electrons both with an up spin or both with a down spin)
what is an electron
An electron is considered to be a cloud of negative charge
What does the negative charge cloud (electron) have the shape of
The negative charge cloud has the shape of the orbital occupied by the electron
what can we be never certain of in terms of an electron
We can never be certain of the exact location of an electron
What does the atomic orbital show about location of an electron
The atomic orbital shows us a 95% probability of where an electron will exist
a volume in space where there is a 95% probability of finding a maximum of two electrons
types of atomic orbitals
each atomic orbital has a letter
they are s,p,d,f
draw s orbital
https://www.researchgate.net/publication/236217213/figure/fig1/AS:650782764462080@1532170110288/Atomic-s-orbital-and-three-orthogonal-p-orbitals.png
how many s orbitals does every electron shell contain
Every electron shell contains a single s orbital
draw p orbitals
https://www.researchgate.net/publication/236217213/figure/fig1/AS:650782764462080@1532170110288/Atomic-s-orbital-and-three-orthogonal-p-orbitals.png
how many different p orbitals are there
there are three different p orbitals
how many p orbitals do the electron shells contain
Every electron shell apart from the first one contains three p orbitals
how many d orbitals are there
There are five different d orbitals
how many d orbitals do the electron shells contain
Every shell apart from shells 1 and 2 have five d orbitals
how many different f orbitals are there
There are seven different f orbitals
how many f orbitals do the electron shells contain
Shells 4 and above have seven f orbitals
cc
subshells = sublevels
What is a subshell
A subshell is all/consists0 of the orbitals of the same type in he same shell
e.g. the 1 s subshell - s in shell 1
2p subshell - p p p in shell 2
3d subshell - d d d d d in shell 3
4f subshell - f f f f f f f in shell 4
https://slideplayer.com/5939515/20/images/33/Principle+energy+level+(n)+Type+of+sublevel.jpg
what do different subshells have
how does this property change, as we move away from the nucleus
Different subshells have different energies
As we move away from the nucleus, the energy of the subshells increases
shell 1 - 1s - lowest
shell 2 - 2s
………. 2p
shell 3 - 3s
shell 3 - 3p - highest
rules to show how electrons fill the orbitals
Rules for filling atomic orbitals
Orbitals with the lowest energy are filled first
We can have up to two electrons in the same orbital but they must have opposite spins
If we have orbitals with the same energy, then we put electrons into individual orbitals before we pair them
That is because electrons in the same orbital repel
things to notice when putting electrons into orbitals
with H has 1e-
the lowest energy l-orbital is 1s orbital in shell 1
half arrow to show the electron’s spin
electron configuration - shorthand version showing just the subshells
electron configuration of Hydrogen
1s1
draw the electrons in their orbitals for nitrogen and state the electron configuration
1s2 2s2 2p3
all p orbitals in 2p subshell have the same energy
if we have orbitals with the same energy we put electrons into individual orbitals before we pair them
electron configuration does not show the individual orbitals in the 2p subshell
this is because the electron configuration only shows the subshells not the individual orbitals
how many orbitals does the d subshell contain
D subshell contains 5 orbitals
what is special about the 4s subshell
The energy of the 4s subshell is less than the energy of the 3d subshell (orbitals in 3d subshell)
This means that we will fill the 4s subshell before we start filling the 3d subshell
Electron configuration of iron
Draw/assigning electrons in their orbitals
how we assign electrons to different atomic orbitals
1s2 2s2 2p6 3s2 3p6 3d6 4s2
how is the electron configuration always written
The electron configuration is always written in the order of the electron shells - not the order of filling
What two exceptions are there for electron configuration
Chromium
Copper
Write out the expected and actual electron configuration for chromium
Chromium - Expected
1s2 2s2 2p6 3s2 3p6 3d4 4s2
Chromium - Actual
1s2 2s2 2p6 3s2 3p6 3d5 4s1
Write out the expected and actual electron configuration for copper
Copper - Expected
1s2 2s2 2p6 3s2 3p6 3d9 4s2
Copper - Actual
1s2 2s2 2p6 3s2 3p6 3d10 4s1
Describe how chromium and copper are different
Don’t follow rules of electron configuration/assigning electrons to orbitals
In both cases, the 4s subshell contains only one electron even though there are electrons in the 3d subshell
Explain the reason why chromium and copper are different
Answer: 3d subshell
The 3d subshell is more stable when it is either half full or completely full
In the case of chromium, by having only one electron in the 4s subshell it can have a half full 3d subshell
In the case of copper, by only having one electron in the 4s subshell, it can have a completely full 3d subshell
State the link between the electron configuration of an element with its place in the periodic table
Periodic table can be divided into different blocks
Each block is named after the subshell containing the highest energy electron for the element of that block
In the S block
In all of these elements, the highest energy electron is in an s subshell
For the elements in the p block, the highest energy electron is in a p subshell
In the d block, the highest energy electron in all of the elements is in a d subshell
For all of the elements in the f block, the highest energy electron is in an f subshell
All orbitals in the same subshell have the same_______
All orbitals in the same subshell have the same energy
Label the periodic table in terms of blocks
e..g silicon 2nd element in p subshell
what do periods represents
the number of electron shells an atom has
