6 - electronic structure

Question 1

What is a shell?

Answer 1

An energy level which electrons are arranged in

The further away the shell from the nucleus, the higher the energy level

Question 2

What is the other term for shells and how is it used?

Answer 2

The principal quantum number

The fourth shell has a principal quantum number of n = 4

Question 3

Define orbital

Answer 3

A region within an atom which can hold up to 2 electrons which will have opposite spins

Question 4

What is spin?

Answer 4

The direction in which an electron spins

An electron can spin up or spin down

when an electron is al

Question 5

Why do orbitals have 2 electrons of opposite spin?

Answer 5

Oppositely spinning electrons pair up naturally in order to reduce repulsion

Question 6

How do you draw an orbital as a diagram?

Answer 6

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

Question 7

What are the 4 orbital types?

Answer 7

S-orbitals
P-orbitals
D-orbitals
F-orbitals

Question 8

Describe an S-orbital and how it fits into electronic structure

Answer 8

It has a spherical shape

Every shell has a single S-orbital

S-orbitals provide space for 2 electrons in each shell

Question 9

Describe a P-orbital and how it fits into electronic structure

Answer 9

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)

Question 10

Describe how D-orbitals fit into electronic structure

Answer 10

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

Question 11

Describe F-orbitals

Answer 11

7 orbitals per shell

Space for 14 electrons per shell

One set of 7 F-orbitals per shell after n = 4

Question 12

How do you find the number of electrons in a shell from the principal quantum number?

Answer 12

Take the principal quantum number

Square it

Double it

That’s the number of electrons in that shell

Question 13

What is a sub-shell?

Answer 13

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

Question 14

How do the electrons fill the different orbitals and shells?

Answer 14

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

Question 15

How do you write the electronic configuration of an atom?

Answer 15

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

Question 16

How would you abbreviate a noble gas electronic configuration?

Answer 16

Just write the symbol of the noble gas in brackets

Question 17

Write the electronic configuration of nickel (28 electrons)

why is the order strange?

Answer 17

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

Question 18

Describe the process of calculating the electronic configuration of an ion

Answer 18

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

Question 19

Calculate the electronic configuration of Li +

The proton number of lithium is 3

Answer 19

3 electrons in lithium atom

Charge is +

2 electrons in Li +

So the electronic configuration is 1s^2

Abbreviated to (He)

Question 20

What do you have to do to calculate the configuration of the ion of a transition metal?

Answer 20

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

Question 21

How does electronic configuration fit into the periodic table?

Answer 21

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