The periodic table 3.1

Question 1

How are elements arranged in the modern periodic table?

Answer 1

In order of increasing atomic number

Question 2

What is periodicity?

Answer 2

The repeating patterns of physical and chemical properties across a period

Question 3

What leads to periodicity?

Answer 3

That all elements in a period have the same number of electron shells

Question 4

What is an orbital?

Answer 4

A region around the nucleus that can hold up to 2 electrons with opposite spin

Question 5

What is a shell?

Answer 5

A group of orbitals in the same energy level (energy level)

Question 6

What is a sub shell?

Answer 6

A group of the same type of atomic orbital within a shell

Question 7

When does ionisation happen?

Answer 7

when atoms gain or lose electrons

Question 8

What is the first ionisation energy?

Answer 8

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

Question 9

What is second ionisation energy?

Answer 9

The energy required to remove one electron from each atom ion in 1 mole of gaseous 1+ ions of an element to form 1 mole of gaseous 2+ ions

Question 10

What are the rules for writing out first ionisations?

Answer 10

• write a gas symbol next to an element even if it is not a gas
• write the ion as positive even if it may be of a different charge

Question 11

What are the factors affecting the first ionisation energy

Answer 11

• atomic radius
• nuclear charge
• electron shielding

Question 12

How does first ionisation energy change as you move across a period?

Answer 12

It increases overall

Question 13

How does atomic radius change as you move across a period?

Answer 13

It decreases

Question 14

How does nuclear charge change as you move across a period?

Answer 14

It increases

Question 15

How does electron sheilding change as you move across a period?

Answer 15

It remains constant

Question 16

What effect does atomic radius have on first ionisation energy across a period?

Answer 16

It increases it

Question 17

What effect does nuclear charge have on first ionisation energy across a period?

Answer 17

It increases it

Question 18

What effect does electron shielding have on first ionisation energy across a period?

Answer 18

It has no effect

Question 19

Is more or less energy needed in sucessive ionisations?

Answer 19

More energy is needed

Question 20

Why is there a decrease in the ionisation energies between the group 2 and 13 elements?

Answer 20

Group 13 have the outer electron in a P orbital and group 2 have it in a S orbital, P orbitals have higher energy so are further away from the nucleus and are easier to remove

Question 21

Why is there a decrease in the ionisation energies between the group 15 and 16 elements?

Answer 21

In groups 13, 14 and 15 each P orbitals contain 1 electron and they begin to get spin paired in group 16, they experience more repulsion and makes them easier to remove

Question 22

Why is there a sharp decrease in ionisation energy between the end of one period and the start of another?

Answer 22

With the addition of a new shell it increases the distance of that shell from the nucleus and increases the electron shielding

Question 23

What happenes to the ionisation energies as you move down a group?

Answer 23

It decreases

Question 24

Why does ionisation energy decrease as you move down a group?

Answer 24

• number of shells increases
• shielding increases
• atomic radius increases
  (nuclear charge has no effect)

Question 25

What are the characteristics of metallic bonding?

Answer 25

- cations are in fixed positions - delocalised electrons between ions - electrostatic attraction between ions and delocalised electrons produces the bond

Question 26

What structure do metals form?

Answer 26

Giant metal lattice structures

Question 27

What are the properties of giant mettalic lattices?

Answer 27

- high melting and boiling points - good electrical conductivity - malleability and ductility

Question 28

Why do metals have a high melting and boiling point?

Answer 28

The atrraction between the positive ions and negative freemoving electrons is very strong and a lot of energy is needed to overcome the mettalic bonds which results in a high temperature

Question 29

Why do metals have good electrical conductivity?

Answer 29

The delocalised electrons are free moving and they can carry charge even in a solid state resulting in electrical conductivity

Question 30

Why are metals malleable and ductile?

Answer 30

Since the electrons are free to move the structure has a degree of 'give' which allows atoms to slide past eachother

Question 31

What does ductile mean?

Answer 31

Can be drawn out or streched

Question 31

What does malleable mean?

Answer 31

Can be hammered into different shapes

Question 32

What happens to the boiling point as you move across the period with metals?

Answer 32

The boiling point increases

Question 33

What is charge density?

Answer 33

The ratio of ions' charge to its size

Question 34

How does the number of free electrons affect the strength of the force?

Answer 34

The more free electrons per cation the stronger the forces of attraction

Question 35

What structure does silicon have?

Answer 35

Macromolecular structure

Question 36

What does a recation between a group 2 metal and water create?

Answer 36

Metal hydroxide + hydrogen

Question 37

How does solubility change as you move down group 2?

Answer 37

It increases

Question 38

How does the boiling point change as you move down the halogen group?

Answer 38

It increases

Question 39

Which does boiling point increase as you move down the halogen group?

Answer 39

Since they have extra shells of electrons which leads to more stronger london forces between molecules

Question 40

How does reactivity change as you move down group 7?

Answer 40

It decreases

Question 41

Why does reactivity decrease down group 7?

Answer 41

- atomic radius increases - electron shielding increases - the ability to gaon an electron in the P subshell to form an ion decreases

Question 42

What colour do the halogens form in water?

Answer 42

- Cl2 = pale green - Br2 = orange - I2 = brown

Question 43

What colour do halogens form in a non polar solvent (cyclohexane)?

Answer 43

- Cl2 = pale green - Br2 = orange - I2 = violet

Question 44

What is a disproportionation reaction?

Answer 44

A reaction in which the same element is both oxidised and reduced

Question 45

How do you test for carbonate ions (CO3 -2)?

Answer 45

- add a dilute strong acid to the solution - Collect any gas formed and pass it through limewater

Question 46

What is a positive result for a carbonate ion test?

Answer 46

- colourless gass produces - gas turns limewater cloudy

Question 47

How do you test for sulfate ions (SO4 -2)?

Answer 47

- add dilute hydrochloric acid and barium chloride to the solution

Question 48

What is a positive result for a sulfate ion test?

Answer 48

- white precipitate of barium sulfate is produced

Question 49

How do you test for halide ions (Cl, Br, I)?

Answer 49

- dissolve solution in water - add aqueous solution of silver nitrate - note the colour of precipitate formed - add aqueous ammonia if colour is hard to tell - note solubility of the precipitate in ammonia

Question 50

What is a positive result for a halide ion test?

Answer 50

- silver chloride - white precipitate + soluble in dilute ammonia - silver bromide - cream precipitate + soluble in conc. ammonia - silver iodide - yellow precipitate + insoluble in ammonia

Question 51

How do you test for ammonium ions (NH4+)?

Answer 51

- add sodium hydroxide solution to the solution - warm gently - test any gas produced with red litmus paper

Question 52

What is a positive result for an ammonium ion test?

Answer 52

- ammonia gas will turn litmus paper blue - ammonia gas has a distinctive smell