EL3 - Shells, Sub-Shells and Orbitals Flashcards
Electrons, where would we be without them?
What is the principal quantum number?
Shell
Given as n (i.e. 1,2,3 etc. the number before the letter…)
The higher the value, the higher the energy
What are shell divided into?
Sub-shells
Labelled s, p, d, and f
What is each sub-shell divided into?
What are its properties?
Atomic orbitals
Each can hold max of 2 electrons
These electrons must have opposite (or paired) spinds
Represented by boxes. Arrows drawn in them represent electrons
How many orbitals does the s subshell contain?
1 s-orbital
Summarise the way in which electrons are organised in atoms, starting with the largest grouping.
(3)
Shell/PQN
Sub-shells
Atomic orbitals
What are the different shapes of the p orbital
px-orbital
py-orbital
pz-orbital
The three orbitals are aligned along perpendicular axis
How many orbitals does the p subshell have?
3
How many orbitals does the d subshell have?
5
How many orbitals does the f subshell have?
7
What are the rules that determine the distribution of electrons in atomic orbitals?
- The orbitals are filled in order of increasing energy
- Where there is more than one orbital at the same energy, the orbitals are first occupied by a single electron. When each orbital is singly occupied, the electrons pair up in the orbitals
- Electrons in singly occupied orbitals have parallel spins
- Electrons in doubly occupied orbitals have opposite (paired) spins
What are the 2 ways of representing electron distribution?
By writing out the electronic configuration in full
e.g. 1s22s22p5
By drawing the electronic configuration in boxes…
What is the shape of the s-orbital?
Spherical
What subshells are in each shell?
The n=1 shell has only an s-subshell.
The n=2 shell has the s and p subshells.
The n=3 shell has the s, p and d subshells.
The n=4 shell has the s, p, d and f subshells.
How many electrons are held in different types of subshells?
The n=1 shell can hold two electrons in the s subshell.
The n=2 shell can hold two electrons in the s subshell and six electrons in the p subshell.
(8 in total)
The n=3 shell can hold two electrons in the s subshell, six electrons in the p subshell and 10 electrons in the d subshell.
(18 in total)
The n=4 shell can hold two electrons in the s subshell, six electrons in the p subshell, 10 electrons in the d subshell and 14 electrons in the f subshell.
(32 in total)
The energy of a subshell is not fixed, but falls as …
the charge on the nucleus increases from one element to the next in the periodic table.
After nickel, the 3d subshell has lower energy than…
Because…
4s
there is an overlap in energy between the n=3 and n=4 shells
An s subshell always contains
__ s-orbital.
A p subshell always contains
__ p-orbitals.
A d subshell always contains
__ d-orbitals.
An f subshell always contains
__ f-orbitals
s - 1
p - 3
d - 5
f - 7
How many electrons can each atomic orbital hold at maximum?
2
NOTE:
Every electron spins at the same rate in either a clockwise (^) or anticlockwise (v) direction.
Electrons can only occupy the same orbital if…
They have opposite spins.
They can be written as
an up arrow and down arrow in a box.
The box represents the atomic orbital and the arrows represent the electrons.
What four pieces of information are needed when describing an electron?
The electron shell it’s in
Its subshell
Its orbital within the subshell
Its spin
The orbitals are filled up in order of…
increasing energy.
In terms of filling up atomic orbitals, what happens when there is more than one orbital with the same energy?
Why?
These orbitals are first occupied singly by electrons.
This keeps electrons in an atom as far apart as possible.
Only when every orbital is singly occupied do the electrons pair up in orbitals.
For the lowest energy arrangement, electrons in singly occupied orbitals have parallel spins.
NOTE: Aufbau Diagram (triangle w arrows)
1s 2s 2p 3s 3p 3d 4s 4p 4d 4f 5s 5p 5d 5f (5g) 6s 6p 6d (6f 6g 6h) 7s 7p (7d 7f 7g 7h 7i)
s holds up to 2
p holds up to 6
d holds up to 10
f holds up to 14
NOTE: Aufbau Diagram (triangle w arrows)
1s 2s 2p 3s 3p 3d 4s 4p 4d 4f 5s 5p 5d 5f (5g) 6s 6p 6d (6f 6g 6h) 7s 7p (7d 7f 7g 7h 7i)
s holds up to 2
p holds up to 6
d holds up to 10
f holds up to 14
1s^2
What does the 1 s ^2 refer to?
1s^2
The electron is in the first electron shell.
The electrons are in an s type orbital.
There are two electrons in this orbital.
