1: Atomic Structure and the Periodic Table

Question 1

What is the atomic number?

Answer 1

Number of protons

Question 2

What is the mass number?

Answer 2

Number of protons and neutrons

Question 3

What is the relative mass of each particle?

Answer 3

Proton - 1
Neutron - 1
Electron- 0.0005

Question 4

What is an isotope?

Answer 4

Atoms of the same element with different numbers of neutrons

Question 5

What are the properties of isotopes?

Answer 5

Same chemical properties (same electrons)

Slightly different physical properties (mass of atom)

Question 6

What is the relative atomic mass (Ar)?

Answer 6

Weighted mean mass of an atom of an element, compared to 1/12 of the mass of an atom of Carbon-12
Average of the relative isotopic masses

Question 7

What is the relative isotopic mass?

Answer 7

Mass of an atom of an isotope compared to 1/12 of the mass of an atom of Carbon-12
Usually a whole number

Question 8

What is the relative molecular mass?

Answer 8

Average mass of molecule compared to 1/12 of the mass of an atom of the carbon-12

Question 9

What is the calculation for the relative atomic mass?

Answer 9

Multiply each isotopic mass by % abundance, add them up

Then divide by 100

Question 10

What are mass spectrometers?

Answer 10

Devices which find out what samples are made up of by measuring the masses of their components

Question 11

What do mass spectrometers produce?

Answer 11

Mass spectra

Question 12

What is on the y-axis of a mass spectra?

Answer 12

Abundance of ions (percentage)

Height of peak gives relative isotopic abundance

Question 13

What is on the x-axis of a mass spectra?

Answer 13

m/z

Mass/charge ratio, most charges are +1 so usually just relative isotopic masses

Question 14

How would you work out the relative atomic mass using a mass spectra?

Answer 14

Multiply relative isotopic mass by abundance and add up results
Divide by sum of the isotopic abundances

Question 15

What are the 4 stages of mass spectroscopy?

Answer 15

Ionisation
Acceleration
Deflection
Detection

Question 16

What happens in the ionisation stage of mass spectroscopy?

Answer 16

Sample bombarded with high energy electrons (causes one electron removed from each atom of sample)

Question 17

What happens in the acceleration stage of mass spectroscopy?

Answer 17

All particles in sample accelerated to same kinetic energy

Question 18

What happens in the deflection stage of mass spectroscopy?

Answer 18

Electromagnet creates magnetic field which deflects ions different amounts based on their m/z
Smaller the m/z, the larger the deflection

Question 19

What happens in the detection stage of mass spectroscopy?

Answer 19

Ions hit detector which creates a current

The current is detected, amplified and recorded

Question 20

What fields is mass spectroscopy used?

Answer 20

Radioactive dating
Space research
Sport to detect illegal drugs
Pharmaceutical industry

Question 21

How would you calculate the isotopic mass from relative atomic mass and 2/3 isotopic masses?

Answer 21

Work out % abundance of unknown

Using Ar of element and the other two isotopes work out mass of isotope

Question 22

What is the M peak?

Answer 22

Molecular ion peak - peak with highest m/z vlaue

Occurs due to formation of the molecular ion from the ionisation process

Question 23

What are the first 4 energy subshells?

Answer 23

s
p
d
f

Question 24

What is an orbital?

Answer 24

Bit of space that electrons move in

Electrons in the subshell have the same energy

Question 25

What can be held in each orbital?

Answer 25

2 electrons

Question 26

What happens to the 2 electrons in an orbital?

Answer 26

Spin-pairing | Electron spin in opposite directions

Question 27

How many orbitals are found in the s sub-level?

Answer 27

1 orbital - 2 electrons

Question 28

How many orbitals are found in the p sub-level?

Answer 28

3 orbitals - 6 electrons

Question 29

How many orbitals are found in the d sub-level?

Answer 29

5 orbitals - 10 electrons

Question 30

How many orbitals are found in the f sub-level?

Answer 30

7 orbitals - 14 electrons

Question 31

What is the first ionisation energy?

Answer 31

Energy required to remove 1 mole of electrons from 1 mole of atoms of a gaseous element to form gaseous ions

Question 32

What is the example equation for the first ionisation energy?

Answer 32

X (g) -> X+ (g) + electron

Question 33

What is the example equation for the second ionisation energy?

Answer 33

X+ (g) -> X2+ (g) + electron

Question 34

What factors affect ionisation energy?

Answer 34

Distance from nucleus Nuclear charge (no. of protons) Shielding

Question 35

Why does 1st ionisation energy decrease as you go down groups?

Answer 35

Effective nuclear charge doesn't change Distance from nucleus increases Shielding increases

Question 36

Why does 1st ionisation energy increase as you go across periods?

Answer 36

Effective nuclear charge doesn't change Distance from nucleus decreases a very small amount Shielding

Question 37

Why does ionisation energy drop from phosphorus to sulphur?

Answer 37

Phosphorus - 3 electrons in the outer sub-level fill up each orbitals Sulphur - 4 electrons mean that two electrons are in one orbital, they repel each other and therefore less energy required

Question 38

What is the exception with subshell notation?

Answer 38

4s subshell has a lower energy level than the 3d subshell | 4s fills up first

Question 39

What is the electronic configuration of chromium?

Answer 39

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

Question 40

What is the electronic configuration of copper?

Answer 40

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

Question 41

What is the electromagnetic spectrum?

Answer 41

Energy that is transmitted as waves with a spectrum of frequencies

Question 42

What are electron shells also known as?

Answer 42

Quantum cells | Energy levels

Question 43

What is excitation?

Answer 43

Electrons take in the energy from their surroundings and move to a higher energy level

Question 44

What happens in de-excitation?

Answer 44

Electrons release specific amounts of energy and drop to a lower energy level Produces a specific frequency of light

Question 45

How can the emission spectra be displayed?

Answer 45

Line spectra of discrete coloured lines | Each spectrum for each element is different

Question 46

What are the four basic principles of quantum shells?

Answer 46

Only exists in fixed orbits Fixes energy When electrons move between orbits EM radiation is emitted or absorbed Radiation will have a fixed frequency

Question 47

Why is the 1st ionisation energy of O less than N?

Answer 47

``` The extra electron of oxygen will cause it to go into an orbital with another electron (2p4) Nitrogen is (2p3), therefore only one electron in each orbital ```

Question 48

What is constant with elements in the same period?

Answer 48

Same number of electron shells

Question 49

What is constant with elements in the same group?

Answer 49

Same number of electrons in their outer shell (similar chemical properties)

Question 50

What is periodicity?

Answer 50

Repeating pattern in physical (and other) properties across period 2 & 3

Question 51

How does atomic radius change across a period?

Answer 51

Decreases - as protons increases so the positive charge increases and electrons are pulled closer

Question 52

What is the s-block?

Answer 52

Group 1 and 2, outer electron always in s-orbital | Easily loses electron

Question 53

What is the d-block?

Answer 53

Most transition metals in the central block, outer electron in d-orbital

Question 54

What is the p-block?

Answer 54

Groups 3-0, outer electron in p-orbital

Question 55

How does boiling point change across period 2 and 3?

Answer 55

Generally increases to group 4 then decreases to 8

Question 56

What elements in group 2 has the highest and lowest boiling temperature?

Answer 56

Highest - Carbon (Group 4) | Lowest - Neon (Group 8 )

Question 57

Explain the trend of melting/boiling points across a period

Answer 57

Group 1-3 have metallic bonding, increasing in strength due to increased charge density Group 4 has giant covalent lattice and strong covalent bonds Groups 6-7 simple molecular structures Group 8 noble gases

Question 58

Why do noble gases have low boiling points?

Answer 58

Exist as individual atoms and therefore have very weak London forces

Question 59

Why does Sulphur have an unusually high boiling/melting point?

Answer 59

Naturally occurs as S8 | Larger London forces as more electrons

Question 60

What block of the periodic table is chromium found?

Answer 60

d | 1s2 2s2 2p6 3p6 4s2 3d4

Question 61

What will have the highest to lowest ionisation of the following species: S S+ S-

Answer 61

Highest: S+ S Lowest: S-

Question 62

What would be the groups of the elements (with consecutive atomic numbers) with the following ionisation energies: 1680, 2080, 496, 738

Answer 62

7, 8, 1, 2

Question 63

Why do increasing numbers of protons not have a large effect if there are also more electrons?

Answer 63

Extra shells and electrons meaning the force is spread more and therefore effectively the same