periodicity

Question 1

how are the elements arranged in a periodic table

Answer 1

in the order of increasing atomic (proton) number

Question 2

how are the periods organised

Answer 2

showing periodicity (repeating trends in physical and chemical properties)

Question 3

how are groups organised

Answer 3

with similar chemical properties

Question 4

definition of first ionisation energy

Answer 4

the energy required to remove one electron from each atom in one mole of the gaseous element to form one mole of gaseous 1+ ions

Question 5

Write an equation for the first ionisation energy of magnesium

Answer 5

Mg(g) -> Mg+(g) + e-

Question 6

definition of second ionisation energy

Answer 6

the energy required to remove of one electron from each atom in one mole of gaseous 1+ ions to form one mole of 2+ ions.

Question 7

what are the three factors that affect ionisation energy

Answer 7

atomic radius
nuclear charge
electron shielding

Question 8

As atomic radius increases first ionisation energy ___

Answer 8

decreases because Attraction Is lower

Question 9

As nuclear charge (protons) increases first ionisation energy ___

Answer 9

Increases because there’s a bigger attraction

Question 10

As electron shielding increases first ionisation energy ____

Answer 10

Decreases because there is weaker attraction as inner electrons repel the outer electrons

Question 11

why does first ionisation energy decrease between group 2 to 3

Answer 11

in group 3, the outer most electron is in subshell p which has a higher energy level than subshell s so the electron is easier to remove

Question 12

why does first ionisation energy decrease between group 5 to 6

Answer 12

until group 5 the electrons in p orbital are single electrons and in group 6 one becomes spin paired with some repulsion so the electrons are easier to remove

Question 13

does first ionisation increase or decrease between the end of one period and the start of another and why

Answer 13

decrease because there is an increase in atomic radius

Question 14

does first ionisation increase or decrease along a period and why

Answer 14

It increases because atomic radius decrease due to nuclear charge increasing so attraction increases but shielding stays the same

Question 15

does first ionisation increase or decrease down a group and why

Answer 15

• decrease
• more shells so electron shielding increases- weaker attraction
• atomic radius increases - more distance from Nucleus and Outermost Electron so there is a weaker attraction
• so increasing nuclear charge (no of protons) increasing attraction is outweighed

Question 16

what are the properties of giant metallic lattices

Answer 16

high melting and boiling point
good electrical conductors
malleable - can be shaped
ductile - can be stretched

Question 17

what group was missing in Mendeleev’s table an why

Answer 17

group 18 because they are highly unreactive noble gases and they had not been discovered

Question 18

What is metallic bonding

Answer 18

strong force of attraction between positive metal ions and sea of delocalized electrons

Question 19

why do metals have high electrical conductivity

Answer 19

The mobile electrons can move through the structure carrying a charge

Question 20

Why do metals have high melting and boiling

Answer 20

This is due to the strong attraction between positive metal ions and negative electrons

Question 21

Why are solid metals insoluble

Answer 21

Metallic bonding is too hard to break

Question 22

What is a simple molecular structure?

Answer 22

substance made of millions of small molecules with strong covalent bonds between atoms and weak intermolecular forces between molecules

Question 23

Why do simple molecular substances have low melting and boiling points?

Answer 23

Weak intermolecular bonds don’t require a lot of energy to break

Question 24

Do simple molecular substances conduct electricity?

Answer 24

No, because there are no mobile charge carriers in the structure

Question 25

Why are simple molecular structures insoluble in water?

Answer 25

They are not polar, so aren’t attracted to polar water molecules

Question 26

What is giant covalent structure?

Answer 26

A large number of atoms joined by many strong covalent bonds

Question 27

Do giant covalent structures have high or low melting points?

Answer 27

They have very high melting points because large amount of energy is needed to break the many strong covalent bonds

Question 28

are giant covalent structures soluble and why

Answer 28

They are insoluble because covalent bonds are too strong to be broken by solvents

Question 29

Why is diamond very hard?

Answer 29

There are many covalent bonds that need lots of energy to overcome

Question 30

Why does diamond not conduct electricity?

Answer 30

There are no delocalised electrons to carry charge as each carbon has four bonds

Question 31

Why is graphite soft and slippery?

Answer 31

Because of the weak intermolecular forces of attraction between each graphene layers

Question 32

Does graphite conduct electricity and why?

Answer 32

Yes, because there are only three carbon bonds so one localised electron to carry charge through the structure

Question 33

Is silicon hard or soft?

Answer 33

It is hard and needs lots of energy to overcome strong covalent bonds

Question 34

Does silica conduct electricity?

Answer 34

No, because of four carbon bonds no delocalised electrons

Question 35

How does graphene conduct electricity?

Answer 35

There is only three carbon bonds, so one delocalised electron to carry charge through the structure

Question 36

What is a giant metallic lattice?

Answer 36

giant structures of metal atoms arranged in a regular pattern loses its outer shell electrons to become a positive metal ion. This leads to a structure of positive ions with negative electrons held together by strong electrostatic forces of attraction

Question 37

Why are metals malleable (mouldable)

Answer 37

because the layers of metal ions that are the same size and arranged in a regular pattern can slide over each other when a force is applied.

Question 38

Why are metals ductile?(can turn into a thin wire)

Answer 38

Because the layers of positive ions are able to slide over each other creating a thin wire

Question 39

why does first ionisation energy increase from group 1 to 2

Answer 39

As nuclear charge increases, so there's a stronger attraction between the nucleus and electrons

Question 40

What is the bonding across period two?

Answer 40

li and be - giant metallic b and c - giant covalent n2, o2, f2, ne - simple molecular

Question 41

What is the bonding across period three?

Answer 41

na, mg, al - giant metallic si - giant covalent p4, s8, cl2, ar - simple molecular

Question 42

Which one has Strongest London forces and therefore higher melting point - phosphorus15 sulphur16 or chlorine17?

Answer 42

sulphur because It forms S8 So has many electrons that form many London forces

Question 43

Why successive ionisation energies always increase

Answer 43

As each electron is removed the outer shell is drawn closer to the nucleus, nuclear attraction increases and more energy is needed to remove the next electron

Question 44

why do Ionic lattices conduct electricity when molten and not when solid

Answer 44

giant ionic lattices have no mobile ions when ions are in a fixed position but when molten the ionic lattice collapses and the ions are now able to move and conduct electricity

Question 45

Why does melting point increase across the Metallic elements of the periods

Answer 45

The metal ions have a greater positive charge meaning The number of delocalised electrons in the metallic bond increases which means attraction Between ions and delocalized electrons increase, requiring more energy to break

Question 46

Why can ionic lattices be good conductors of electricity in liquid state

Answer 46

Ions in the solution can move and carry charge

Question 47

What to include in a metallic lattice diagram

Answer 47

Rows of metallic positive ions with negative electrons surrounding both labelled

Question 48

Explain which block x is in

Answer 48

in y block Because it's highest energy/outer most electron is in the y subshell

Question 49

Out of group two and group three which element has the lowest first ionisation energy, the lowest 4th ionisation energy and the lowest boiling point

Answer 49

Sodium silicon neon

Question 50

There is a large increase between ionisation energy 4th and 5th element explain what this means

Answer 50

Atom has four electrons in the outer shell so the fifth one must be removed from a new shell closer to the nucleus