Periodicity

Question 1

In the 1800’s how did they order the elements of the periodic table?

Answer 1

According to atomic mass

Question 2

How are elements ordered?

Answer 2

By proton number not mass number

Question 3

What is ionisation?

Answer 3

The minimum amount of energy required to remove 1 mole of electrons from 1 mole of atoms in the gaseous state

Question 4

Is ionisation endothermic or exothermic?

Answer 4

Requires energy- they are always an endothermic process therefore they always have a positive value

Question 5

Shielding?

Answer 5

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

Question 6

Atomic size?

Answer 6

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 7

Nuclear charge?

Answer 7

The more protons there are in the nucleus- the bigger the attraction between nucleus and outer electrons
This means more energy is required to remove the electron

Question 8

What happens to ionisation energy as you go down a group?

Answer 8

Ionisation energy decreases.

Question 9

Atomic radius does what when you go down the group?

Answer 9

Increases
The outer electrons are further from the nucleus
The attractive force is weaker
The energy required to remove an electron decreases

Question 10

Shielding does what as you go down a group?

Answer 10

Increases
More shells between the nucleus and the outer shell
Attractive force is weaker
Energy required to remove an electron decreases

Question 11

What happens to ionisation energy as you go across a period?

Answer 11

Increases

Question 12

What happens to the nuclear attraction as you go across a period?

Answer 12

There is an increasing number of protons in the nucleus
This increases the nuclear attraction

Question 13

What happens to shielding as you go across a period?

Answer 13

Similar
Distance from nucleus marginally decreases

Question 14

What happens to the levels of energy needed to remove an outer electron?

Answer 14

Across a period more energy is required to remove an outer electron
Ionisation energy increases

Question 15

What is a decrease at aluminium evidence for?

Answer 15

Atoms having sub-shells

Question 16

What is the outer most electron in aluminium like compared to the outer electron in magnesium?

Answer 16

The outer most electron in aluminium sits in a higher energy sub-shell slightly further from the nucleus than the outer electron in magnesium
Aluminium has 3p1
Magnesium has 3s2

Question 17

What is a decrease at sulphur evidence for?

Answer 17

Electron repulsion in an orbital

Question 18

What are phosphorous’ and sulphurs’ outer electrons like?

Answer 18

They both have outer electrons in the 3p orbital so the shielding is the same

Question 19

What does removing an electron from sulphur involve taking?

Answer 19

Involves taking it from an orbital with 2 electrons in

Question 20

Is more or less energy needed to remove an electron from an orbital with 2 in than one with 1 in?

Answer 20

Less energy as electrons repel eachother

Question 21

What is successive ionisation?

Answer 21

The removal of more than 1 electron from the same atom

Question 22

How many times is each carbon bonded in graphite?

Answer 22

3 times
The 4th electron is delocalised

Question 23

Does graphite have a high or low melting point?

Answer 23

High- lots of strong covalent bonds

Question 24

How do layers slide easily in graphite?

Answer 24

There are weak forces between the layers

Question 25

How does graphite have a low density?

Answer 25

Layers are far apart in comparison to covalent bond lengths

Question 26

Is graphite soluble or insoluble?

Answer 26

Insoluble- the covalent bonds are too strong to break

Question 27

How many times is each carbon bonded in diamond?

Answer 27

4 times in a tetrahedral shape

Question 28

Can diamond conduct heat?

Answer 28

Yes- the tightly packed, rigid arrangement allows heat to conduct well in diamond

Question 29

What can diamond be cut to make?

Answer 29

Gemstones

Question 30

High or low melting point in diamond?

Answer 30

Very high due to many strong covalent bonds Also very hard

Question 31

Does diamond conduct electricity?

Answer 31

No as it does not have any delocalised electrons

Question 32

Is diamond soluble or insoluble?

Answer 32

Insoluble- the covalent bonds are too strong to break

Question 33

What do metals have in terms of structure?

Answer 33

Giant metallic lattice structures

Question 34

How are positive metal ions formed?

Answer 34

Metals donate electrons to form a sea of delocalised electrons

Question 35

What attraction is there between positive metal ions and negative delocalised electron?

Answer 35

Electrostatic attraction

Question 36

How does the melting point in metals become higher?

Answer 36

The more electrons an atom can donate t the delocalised system- the higher the melting point

Question 37

Why does magnesium have a higher melting point than sodium?

Answer 37

Magnesium can donate 2 electrons (group 2) whereas sodium can only donate 1

Question 38

Are metals good thermal conductors?

Answer 38

Yes as the delocalised electrons can transfer kinetic energy

Question 39

Are metals good electrical conductors?

Answer 39

Yes- the delocalised electrons are mobile and can carry a current

Question 40

Are metals good thermal conductors/

Answer 40

The delocalised electrons can transfer kinetic energy

Question 41

Do metals have high or low melting points?

Answer 41

High- due to the strong electrostatic attractions

Question 42

Are solid metals insoluble or soluble?

Answer 42

Insoluble as the metallic bond is too strong to break

Question 43

What happens to melting points in period 3?

Answer 43

General increase in melting points as metal ions have an increasing positive charge Increasing the number of delocalised electrons and smaller ionic radius This means a stronger metallic bond The same trend for period 2 as well

Question 44

Why does silicon have the highest melting point in period 3?

Answer 44

Has a giant covalent structure

Question 45

What type of bonds hold the silicon atoms together?

Answer 45

Many strong covalent bonds- a large amount of energy is needed to overcome these strong covalent bonds

Question 46

Why does phosphorus have a lower melting point than silicon?

Answer 46

Has a weaker simple molecular structure The melting point is determined by weaker induced dipole-dipole forces

Question 47

Why does sulfur have a higher melting point than phosphorus?

Answer 47

Has a larger simple molecular structure Has larger induced dipole-dipole forces and therefore a higher melting point

Question 48

Why does chlorine have a lower melting point than phosphorus and sulfur?

Answer 48

Has a smaller simple molecular structure Has smaller induced dipole-dipole forces- therefore a lower melting point

Question 49

Why does argon have a lower melting point than the rest of the elements in period 3?

Answer 49

It only exists as individual atoms Has smaller induced dipole-dipole forces and therefore a lower melting point

Question 50

Giant covalent state at room temp and pressure?

Answer 50

Solid

Question 51

Simple molecular state at room temp and pressure?

Answer 51

Liquid or gas BUT iodine is a solid

Question 52

Giant ionic and metallic at usual state at room temp and pressure?

Answer 52

Solid Solid