Unit 3.1.1 - Atomic Structure

Question 1

What does atomic number mean?

Answer 1

It is the number of protons in the nucleus of an atom

Question 2

What does mass number mean?

Answer 2

It is the sum of the number of protons in the nucleus of an atom?

Question 3

What is the mass of an electron?

Answer 3

1/1840

Question 4

What is an isotope?

Answer 4

Atoms with the same atomic number but different mass number

Question 5

What is an ion?

Answer 5

Species in which the proton and electron numbers are not the same and so have an overall charge

Question 6

What was Dalton’s model for the atom?

Answer 6

Solid spheres surrounded by an atmosphere of heat, different spheres made up different elements

Question 7

What was Thomson’s model for the atom?

Answer 7

“The Plum Pudding Model” - Negatively charged electrons surrounded by a sphere of positive charge

Question 8

What are Rutherford’s model for the atom?

Answer 8

There was a positively charged nucleus surrounded by orbiting electrons

Question 9

How was Bohr’s different to Rutherford’s model?

Answer 9

The electrons didn’t just orbit the nucleus they occupied shells

Question 10

What did Rutherford find from his experiment - firing alpha particles at a thin sheet of gold?

Answer 10

According to the plum pudding model they expected all the alpha particles to be slightly deflected by the positively charged sphere, however most passed straight through and only a small number were deflected. This meant most of an atom was empty space and there was only a small positive nucleus, this helped him to come up with his model for the atom

Question 11

Define the relative atomic mass of an atom?

Answer 11

The average mass of one atom compared to 1/12th of the mass of one atom of carbon-12

Question 12

Define the relative isotopic mass of an isotope?

Answer 12

The average mass of one atom of that isotope compared to 1/12th of the mass of one atom of carbon-12

Question 13

What can you use to measure the relative abundance of isotopes and what graph does it produce?

Answer 13

Mass spectrometry and a mass spectra

Question 14

Label the different sections in a mass spectrometry?

Answer 14

See flash card 12

Question 15

What are the five sections in a mass spectrometry?

Answer 15

Vaporisation, ionisation, acceleration, deflection and detection

Question 16

What happens during vaporisation in a mass spectrometry?

Answer 16

The sample is heated so that it is vaporised into a gas

Question 17

What happens during ionisation in a mass spectrometry?

Answer 17

High energy electrons are fired out of an electron gun towards the sample to knock of electrons and turn them into ions

Question 18

What happens during acceleration in a mass spectrometry?

Answer 18

The positive ions are accelerated by an electric field

Question 19

What happens during deflection in a mass spectrometry?

Answer 19

The ions are deflected around the bend by a magnetic field

Question 20

Which ions are deflected more during deflection?

Answer 20

Light ions with a smaller m/z ratio

Question 21

What happens during detection in a mass spectrometry?

Answer 21

When ions hit the detector they cause a current to flow, the bigger the current produced the more of that isotope present in the sample

Question 22

How can you get different ions to reach the detector during a mass spectrometry?

Answer 22

Alter the strength of the magnetic field so that different ions are deflected to the detector

Question 23

What happens if you put molecules into a mass spectrometer?

Answer 23

The molecules often break up into fragments because of the high temperatures and conditions

Question 24

What two things does a mass spectra show?

Answer 24

1. ) the m/z ratio of the isotopes

2. ) the relative abundance of the isotopes

Question 25

Do isotopes have similar or different chemical properties and why?

Answer 25

Similar because they have the same electron configuration

Question 26

The shells that electron occupy are also known as?

Answer 26

Energy levels

Question 27

Shells can be broken up into?

Answer 27

Sub - shells

Question 28

Name the sub shells and orbitals in the first 4 shells?

Answer 28

1s, 2s, 2p, 3s, 3p, 3d, 4s, 4p, 4d, 4f

Question 29

How many electrons can an s, p and d orbitals hold?

Answer 29

2, 6, 10

Question 30

Why do you fill from the 4s orbital before the 3d orbital?

Answer 30

Because the 4s has a lower energy level and you always fill the lowest energy level first

Question 31

What two methods can you use to show electron configuration?

Answer 31

Orbital method and the box and arrow diagrams

Question 32

What does the orbital method look like and what does it show?

Answer 32

It shows the energy level, then the sub shell and the number of electrons in the orbital in subscript

1s2, 2s2, 2p6, 3s2, 3p6, 4s2

Question 33

What are the three rules for when drawing box and arrow diagrams?

Answer 33

1. ) electrons fill the lowest energy sub shells first
2. ) electrons fill the orbitals singularly before they start sharing
3. ) when two electrons occupy the same orbital they must do with opposite spin and so the arrows must go in opposite directions

Question 34

Which two elements don’t follow the usual electron configuration rules?

Answer 34

copper and chromium

Question 35

Why doesn’t copper follow the usual electron configuration rules?

Answer 35

As it is more happier with a more stable full d sub shell

Question 36

Why doesn’t chromium follow the usual electron configuration rules?

Answer 36

As it is more happier with a more stable half full d sub shell

Question 37

What rule don’t chromium and copper follow?

Answer 37

Filling the 4s orbital before the 3d orbital

Question 38

What is the electron configuration of copper?

Answer 38

1s2, 2s2, 2p6, 3s2, 3p6, 3d10, 4s1

Question 39

What is the electron configuration of chromium?

Answer 39

1s2, 2s2, 2p6, 3s2, 3p6, 3d5, 4s1

Question 40

Define first ionisation energy?

Answer 40

The energy needed to remove 1 electron from one mole of gaseous atoms to produce one mole of gaseous ions

Question 41

What is the general formula or first ionisation energy?

Answer 41

Y (g) ————> Y+(g) + e-

Question 42

Is ionisation energy exothermic or endothermic?

Answer 42

Endothermic

Question 43

What is ionisation energy endothermic?

Answer 43

Because energy is required to overcome the attraction between the electrons and the nucleus and so energy is taken in

Question 44

What four factors affect first ionisation energy?

Answer 44

Nuclear charge, shielding, distance from the nucleus and electron repulsion

Question 45

How does nuclear charge affect first ionisation energy?

Answer 45

The more protons in the nucleus the greater the positive charge and so greater the attraction to the electrons and so they are harder to remove

Question 46

How does distance from the nucleus affect first ionisation energy?

Answer 46

Electrons further away from the nucleus are less attracted to the nucleus and so are easier to remove

Question 47

How does shielding affect the first ionisation energy?

Answer 47

As the number of electrons between the outer electrons and the nucleus increases the outer electrons feel less attraction and so are easier to remove

Question 48

How does electron repulsion affect the first ionisation energy?

Answer 48

Electrons repel each other when they are in the same orbital and so electrons are easier to remove is they occupy an orbital with another electron

Question 49

Why is second ionisation energy usually always more than first ionisation energy?

Answer 49

It is harder to remove an electron from a positively charged ions because the forces of attraction to the electrons will be greater

Question 50

What is the general pattern in first ionisation energy as you go down group 2?

Answer 50

It decreases

Question 51

Why does first ionisation energy decrease as you go down group 2?

Answer 51

There are more electron shells and so an increasing atomic radius and shielding meaning the outer electrons are less strongly attracted to the nucleus and are easier to remove