3.1.1 Atomic Structure

Question 1

Who discovered atoms?

Answer 1

John Dalton

Question 2

What did John Dalton specifically notice about atoms?

Answer 2

• All atom of a given element are all the same
• All atoms of an elements are different to all atoms of another element

Question 3

What atomic model did JJ Thompson create and how did he do this?

Answer 3

Plum Pudding Model
Used cathode rays to discover electrons (due to the rays deflecting by magnetic and electric fields)

Question 4

What did Ernest Rutherford do to develop the model of the atom?
Describe his observations and deductions and name the newly developed model.

Answer 4

He directed alpha particles towards thin gold foil and measured the particles’
deflection

• Most alpha particles went
  straight through (mostly empty
  space)
• Some Alpha particles deflected
  at an angle (the charge
  concentrated at the center
  and is positive
• Very little alpha particles
  deflected straight back (mass is
  concentrated at the center)

Question 5

What did Niels Bohr discover about electrons?
What else did he discover?

Answer 5

He discovered that electrons orbit in fixed orbits and energy levels

Each energy level has fixed energy

Electron can move between shells with an energy change

He also discovered protons

Question 6

Chronological order of the Models of the Atom?

Answer 6

• Sphere Model by John Dalton
• Plum pudding model by JJ
  Thomson
• Nuclear model by Ernest
  Rutherford
• Planetary model by Niels Bohr

Question 7

What is the difference between the sphere model and plum pudding model?

Answer 7

Presence of electrons

Question 8

What is the difference between the plum pudding model and Nuclear model?

Answer 8

Central positive charged nucleus surrounded by electron shells

Question 9

What is the difference between the Nuclear model and Planetary model?

Answer 9

It is 3D and shows different orbital levels and shows protons

Question 10

Relative Charge of Protons

Answer 10

1+

Question 11

Relative Charge of Neutrons

Answer 11

0

Question 12

Relative Charge of Electrons

Answer 12

-1

Question 13

Relative Mass of Protons

Answer 13

1

Question 14

Relative Mass of Neutrons

Answer 14

1

Question 15

Relative Mass of Electrons

Answer 15

1/2000

Question 16

What are the fundamental particles present in an atom and how are they arranged?

Answer 16

An atom consists of a nucleus containing protons and neutrons and is surrounded by electrons

Question 17

What is the mass number?

Answer 17

Mass number is the top number of an element which shown the total amount of protons and neutrons present in an atom

Question 18

What is the atomic number?

Answer 18

Atomic number is the bottom number of an element which shows the amount of protons an element has

Question 19

What is an isotope?

Answer 19

They are atoms of the same element with different numbers of neutrons

Question 20

What properties differ about an Isotope of an element

Answer 20

Its physical properties (different density or rate of diffusion)

Question 21

What are all the stages of a (TOF) Mass Spectrometer

Answer 21

• Ionisation
• Acceleration
• Ion drift
• Ion detection
• Data analysis

Question 22

What are the 2 types of Ionisation?

Answer 22

• Electron Impact
• Electrospray

Question 23

What is the process of Electron Impact ionisation?

Answer 23

The sample is vaporised and an electron gun is used to fire high energy electron at it, this knocks off one electron off each particle so they become 1+ ions

Question 24

What is the process of Electronspray ionisation?

Answer 24

The sample is dissolved in a volatile solvent and pushed through a small nozzle at high pressure. A high voltage is applied to it causing each particle to gain an H+ ion. The sample is turned into a gas made up of positive ions

Question 25

How are the ions accelerated during (TOF) Mass spectrometry Which ions are quicker ?

Answer 25

Positively charged ions are accelerated by an electric field so that they all have the same kinetic energy (lighter ions will travel faster than heavier ones)

Question 26

What is Ion drift in (TOF) Mass Spectrometry?

Answer 26

Ions enter region with no electric field so they just drift (Lighter ions will drift faster than heavier ions)

Question 27

What is Detection in (TOF) Mass Spectrometry?

Answer 27

Detectors detects (Lighter ions quicker) charged particles as a current is produced in the detector and a mass spectrum is produced

Question 28

What are the relative masses that (TOF) mass spectrometry can measure?

Answer 28

Relative atomic mass (Can be used to identify elements), Relative molecular mass (Can be used to identify molecules) and relative isotopic abundance

Question 29

What is relative Molecular Mass?

Answer 29

The average mass of a molecule relative to 1/12th of a carbon atom

Question 30

What is Mass Spectrum?

Answer 30

It is Mass/Charge plotted against Abundance

Question 31

How to find out the Relative atomic Mass from a Mass Spectrum?

Answer 31

% abundance times mass/charge all divided by 100

Question 32

What is first ionisation energy?

Answer 32

The energy required to remove 1 electron from each atom in 1 mole of gaseous atoms to form 1 mole of gaseous 1+ ions

Question 33

Equation for first and successive ionisation energies

Answer 33

X -----> X+ + e- X+ ------> X2+ + e-

Question 34

How do first and successive ionisation energies in Period 3 (Na–Ar) and in Group 2 (Be–Ba) give evidence for electron configuration in sub-shells and in shells?

Answer 34

There is a big jump ionisation energy after the outermost electrons are removed shows that a new shell (closer to the nucleus) is being broken into

Question 35

which is the fundamental particle that wouldn't be deflected by an electric field?

Answer 35

Neutron