Atomic Structure

Question 1

What is the principal quantum number of the first and second shell

Answer 1

1 and 2

Question 2

What is an atomic orbital

Answer 2

A region around the nucleus that can hold up to two electrons with opposite spins

Question 3

If there are two electrons in the same orbital what does that tell you about their spins

Answer 3

Must have opposite spins

Question 3

What are the two type of spins that electrons can have

Answer 3

Up spin
Down spin

Question 4

What are the 4 orbitals

Answer 4

s
p
d
f

Question 5

What is a subshell

Answer 5

All of the orbitals of the same type in the same shell

Question 6

What happens to the energy of the shell as it gets further and further away from the nucleus

Answer 6

It increases

Question 7

What is the rule regarding the 4p and 3d subshell

Answer 7

4s has lower energy than 3d so 4s is filled and emptied before 3d

Question 8

What is the electron configuration of Chromium and Copper

Answer 8

Chromium - 1s^2 2s^2 2p^6 3s^2 3p^6 3d^5 4s^1
Copper - 1s^2 2s^2 2p^6 3s^2 3p^6 3d^10 4s^1

Question 9

What is the explanation of the electron configuration of Chromium

Answer 9

The 3d subshell is more stable when it is either halffull or completely full
So Chromium only has one electron in the 4s subshell so it can have a half full 3d subshell

Question 10

What is the explanation of the electron configuration of Copper

Answer 10

The 3d subshell is more stable when it is either half full or completely full
So Copper only has one electron in the 4s subshell so it can have a full 3d subshell

Question 11

What is the short hand electron configuration of Sodium

Answer 11

[Ne] 3s^1

Question 12

What is the short hand electron configuration of Manganese

Answer 12

1s^2 2s^2 3s^2 3p^6 3d^5 4s^2
[Ar] 3d^5 4s^2

Question 13

If there is a 3d subshell why does it appear in short hand configuration

Answer 13

It is shown because 3d electrons can be involved chemical reactions

Question 14

Which has lower energy, 4s or 3d

Answer 14

4s has lower energy

Question 15

What is the configuration of Mn3+

Answer 15

Mn - 1s^2 2s^2 2p^6 3s^2 3p^6 3d^5 4s^2
Mn3+ - 1s^2 2s^2 2p^6 3s^2 3p^6 3d^4

Question 16

What is the first ionisation energy

Answer 16

The energy needed to remove one mole of electrons from one mole of atoms in their gaseous state to form one mole of 1+ ions in their gaseous state

Question 17

What is the second ionisation energy

Answer 17

The energy needed to remove one mole of electrons from one mole of 1+ ions in their gaseous state to form one mole of 2+ ions in their gaseous state

Question 18

What are the three factors that affect ionisation energy

Answer 18

The distance between the nucleus and the outermost electrons
The charge on the nucleus - greater number of protons mean greater attraction
Shielding - outer electrons are repelled by electrons in inner shells and this shielding effect reduces attraction between outer electrons and the nucleus

Question 19

Why does the ionisation energy increase as you keep ionising an atom

Answer 19

Because the remaining outer electrons are pulled slightly closer to the nucleus
This causes a greater attraction between nucleus and electrons causing the ionisation energy to increase

Question 20

If you were to graph the ionisation against the ionisation energy of Oxygen at what ionisation number would you see a spike in ionisation energy and explain

Answer 20

The 7th ionisation energy
There are six electrons on Oxygen’s outer shell so when the 6th electron is removed the 7th electron is much closer to the nucleus and experience less shielding so the attraction is greater

Question 21

What is this period 3 element

Answer 21

Huge spike on the 5th ionisation energy so it has 4 electrons on its outer shell
This means it’s in group 4 so it is Silicon

Question 22

Describe and explain the trend in ionisation energy when you go down a group

Answer 22

Decreaes as you go down
The atomic radius increases - outer electron shell are further away from the nucleus
Number of internal energy levels increase so there is more shielding

Question 23

Describe and explain the trend in ionisation energy across a period

Answer 23

Generally increases
Nuclear charge increases as number of protons increases - this increases attraction between nucleus and electrons and atomic radius decreases
Both of these factors mean the outer electrons are more attracted to nucleus
Increases ionisation

Question 24

What are the two exceptions in the ionisation energy trend in period 2

Answer 24

Boron Oxygen

Question 25

Explain the two exceptions in the ionisation energy trend in period 2

Answer 25

Boron - Berylium has outer electrons in a 2s^2 shell and Boron has the outer electron in a 2p^1 shell; 2p subshell has higher energy than 2s so less energy is needed to remove so lower ionisation energy Oxygen - there are two electrons in a 2p subshell; these electrons repel each other so it is easier to remove one of them so the ionisation energy is lower than Nitrogen

Question 26

What are the two exceptions to the trend of first ionisation energy across period 3

Answer 26

Aliminum Sulfur

Question 27

Explain the two exceptions in the ionisation energy trend in period 3

Answer 27

Aliminium - Has outer electron in 3p subshell rather than 3s so it is further away from the nucleus so it is easier to remove meaning it has a lower ionisation energy than Magnesium Sulfur - 4 outer electrons in 3p subshell and there are two electrons in the same orbital; they repel each other making it easier to lose one electron meaning has it has a lower ionisation energy than Phosphorus

Question 28

Explain the process of a sample going through a time of flight mass spectrometer

Answer 28

Take sample of element and place into sample chamber (sample contains all of the different isotopose of the element) The atoms go through ionisation - converts all of the atoms into positive ions The ions are attracted to a negatively charged plate which attracts the ions and increases the kinetic energy of the ions Once they pass through the plate they stop accelerating and drift down the chamber towards the detector When ions reach detector each positive ions gains electrons from the detector - this transfer of electrons causes a current to flow

Question 28

What is the purpose of a time of flight mass spectrometer

Answer 28

To determine mass and abundance of isotopes

Question 29

How does the time of flight mass spectrometer calculate mass and abundance of the sample isotopes

Answer 29

The time that it takes for the positive ion to move down the chamber to the detector will be used to determine the mass of the isotope The size of the current produced when each isotope hits the detector is used to determine the abundance of each isotope

Question 29

As the current produced by an isotope in the detector increases what happens to the abundance of that isotope

Answer 29

It increases

Question 30

How can you tell from a mass spectrum the amount of isotopes the sample has

Answer 30

Count the peaks in abundance

Question 31

How many isotopes of Copper are there

Answer 31

2 Because there are two peaks

Question 32

What is the m/z ratio

Answer 32

The ratio of the mass of each ion to its charge

Question 33

How many isotopes of Magnesium are there and what are the relative masses of each one

Answer 33

There are 3 The relative masses are - 24, 25, 26

Question 34

What is relative isotopic mass

Answer 34

The mass of an atom of an isotope compared to 1/12th the mass of carbon-12

Question 35

What type of number is relative isotopic mass

Answer 35

Always a whole number and never a decimal

Question 36

What is relative atomic mass

Answer 36

The weighted mean mass of an atom of an elemtent compared with 1/12th the mass of a carbon-12 atom