Atomic Structure

Question 1

What did John Dalton think

Answer 1

1803

Atoms are spheres and each element is made from different spheres

Question 2

What did JJ Thompson think

Answer 2

1897
Discovered the electron. That the atom wasn’t solid and was made up of other particles. The plumb pudding model was developed

Question 3

What is Ernest Rutherford do

Answer 3

1909
Discovered the nucleus. Also discovered that nucleus was very small and positively charged. Concluded that atom was mainly empty space made up of negative cloud

Question 4

What is the gold leaf experiment

Answer 4

fired positive alpha particles at thin gold leaf, most went through ( empty space)
some deflected back ( they hit small positive nucleus) repelled eachother

Question 5

What did Niels Bohr do?

Answer 5

Discovered a problem with Rutherfords model. Cloud of electrons could collapse into positive nucleus, so he proposes electrons were in fixed energy shells

Question 6

what is the experimental proof for niels bohr

Answer 6

when Electromagnetic radiation is absorbed, electrons move between shells, they emit this radiation when electrons move down to lower energy levels

Question 7

What is the atomic model today?

Answer 7

Electrons don’t have the same energy in shells. We have sub shells. Which explain ionisation trends

Question 8

What is the first step for ToF mass spectrometry

Answer 8

1) Vaporisation

sample is vaporised so it can travel through the TOF mass spectrometer

Question 9

Second step of TOF mass spectrometer?

Answer 9

2) Ionisation
Sample is pushed through a nozzle making a high pressure jet. A high voltage is passed through causing the loss of an electron. A gaseous positively charged sample is produced. This is electrospray ionisation

Question 10

Third step of TOF mass spectrometer

Answer 10

3) Acceleration

Positive ions are passed through an electric field. Particles with lower mass/charge (m/z) ratio accelerate quicker

Question 11

Fourth step of ToF mass spectrometer

Answer 11

4) Ion drift
particles travel through with a constant speed and Kinetic energy.
They drift through and particles with lower (m/z) travel faster

Question 12

Fifth step of ToF mass spectrometer?

Answer 12

5) Detection
Ions are detected as electrical current is made when particle hits the plates. Particle with lower m/z reach plate first as they travel faster

Question 13

Relative atomic mass (Ar)

Answer 13

The average mass of an atom of an element
when measured on scale on which the mass of
an atom of 12C is exactly 12.

Question 14

Relative Molecular Mass (Mr)

Answer 14

Relative Molecular Mass (Mr)
The average mass of a molecule when
measured on scale on which the mass of an
atom of 12C is exactly 12.

Question 15

Relative Isotopic Mass

Answer 15

The mass of an atom of an isotope of an
element measured on scalè on which the mass
of an atom of 12C is exactly 22.

Question 16

Relative atomic mass formula

Answer 16

(AbundnaceA × m/zA) + (AbundnaceB x m/zB) / Total Abundance

Question 17

In mass spectra for molecules what does the molecular ion peak mean

Answer 17

last significant peak on spectra, shows unfragmented molecule, it’s m+1
it’s the same as the relative molecular mass of the molecule

Question 18

How many electrons can s shell hold

Answer 18

2

Question 19

How many electrons can p shell hold

Answer 19

6

Question 20

how many electrons can d shell hold

Answer 20

10

Question 21

how many e can f shell hold

Answer 21

14

Question 22

what is lower in energy 3d or 4s

Answer 22

4s

Question 23

How do orbitals fill up

Answer 23

singly first

then they pair up

Question 24

Why do orbitals fill singly

Answer 24

Due to electron repulsion

Question 25

How do chromium and copper behave differently

Answer 25

An electron from the 4s orbital moves into 3d orbital to create a more stable half full subshell

Question 26

How do transition metal ions behave differently

Answer 26

Electrons move from 4s first because it’s more stable and takes less energy

Question 27

What is ionisation

Answer 27

Minimum amount of energy required to remove 1 mole of electrons from 1 mole of atoms in a gaseous state

Question 28

Equation for first ionisation energy with state symbols?

Answer 28

Na (g) -> Na+(g) + e-

Question 29

is ionisation positive or negative and why?

Answer 29

positive because it’s an endothermic process

Question 30

What is the effect of shielding on ionisation?

Answer 30

The more electrons shells
between the positive nucleus and
negative electron that is being
removed the less enerey is
required. There is a weaker
attraction.

Question 31

Effect of atomic size on ionisation?

Answer 31

The bigger the atom the further
away the outer electrons are from
the nucleus. The attractive force
between nucleus and outer
electrons reduces - easier to
remove electrons.

Question 32

Effect of nuclear charge on ionisation?

Answer 32

The more protons in the nucleus
the bigger the attraction between
nucleus and outer electrons. This
means more energy required to
remove the electron.

Question 33

What is successive ionisation?

Answer 33

removal of more than 1 electron from same atom.

Question 34

second ionisation equation

Answer 34

X+ (g) -> X2+ e-

Question 35

What trend can we find in a successive ionisation graph

Answer 35

jump in energy as we remove electrons from shell closer to nucleus

Question 36

trend found in 1st ionisation energy graph ( groups)

Answer 36

ionisation energy decreases as we go down group as atomic radius gets bigger so outer electrons are further from nucleus and attractive force is weaker so energy needed to remove electron decreases

Shielding increases- more space- attractive force weaker- energy decreases

Question 37

trend found in 1st ionisation trends graphs (periods)

Answer 37

Across a period- proton number increases- nuclear attraction increases- ionisation energy increases

Shielding marginally decreases the energy needed but not too significant

More energy required to remove outer electron as ionisation energy increases

Question 38

What elements have a decreases in 1st ionisation energy trend graphs ( period)

Answer 38

Aluminium decreases, as outermost electron in aluminium sits in a higher energy subshell slightly further from the nucleus than the electron in Magnesium, more shielding as Al has an e in a 3p orbital

Sulfur decreases, has the same shielding as phosphorus but removing an electron from sulfur requires less energy as we are removing it from an orbital with 2 electrons in it - which repel eachother