6 - electronic structure Flashcards Preview

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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


Define orbital

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


Describe F-orbitals

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

Square it

Double it

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


How does electronic configuration fit into the periodic table?

Hydrogen and helium only have 1s orbital

The block on the left of the table (group 1 and 2) is the S-block and all electronic configuration end in an S orbital here

The transition metals is the D-block and all configurations in here end in a D orbital

The block on the right is the P-block where all inside end in a P orbital

The block separated at the bottom is the F-block (lanthanides, actinides), all of these end in an F orbital