3.1

Question 1

periodicity

Answer 1

the trends that occur as you move across the periodic table

Question 2

1st ionization energy

Answer 2

the energy needed to remove 1 mol of electrons from 1 mol of gaseous atoms

Question 3

ionisation energy trend

Answer 3

decreases down a group and increases across a period

Question 4

explanation of ionization energy trend

Answer 4

//electrons down a group have more shells+a larger radius-> electron shielding and distance=less attraction to nucleus// across a period more protons and electrons but no new shells so greater effective nuclear charge

Question 5

trend of electronegativity

Answer 5

increases across a period and up a group

Question 6

explanation of electronegativty trend

Answer 6

positive effctive attraction from nucleus is grater

Question 7

atomic radius trend

Answer 7

decreases along a period

Question 8

reason for atomic radius trend

Answer 8

more protons in nucleus, greater effective nuclear charge so the outer electrons are more attracted to the nucleus

Question 9

electrons shielding

Answer 9

repulsion between electron shells

Question 10

group 2 trends

Answer 10

down the group: reactivity increases, ionization energy decreases,atomic radius increases,melting point decreases

Question 11

why does melting point decrease down group 2

Answer 11

the ions get bigger so the electrons holding it all together are further from the positive nucleus so they hold it together with less force

Question 12

why does ionization energy decrease down group 2

Answer 12

outer shell electrons are further from the nucleus and increased electron shielding so its easier to remove them

Question 13

Mg (s) + H20(l) ->

Answer 13

Mg(OH)2 (aq) + H2 (g)

Question 14

Mg (s) + H20(g) ->

Answer 14

MgO (s) + H2 (g)

Question 15

group 7 trends

Answer 15

down the group: atomic radius increases, melting point increases, electronegativity decreases, reactivity decreases down the group, ionization energy decreases down the group

Question 16

explanation of group 7 meting points

Answer 16

induced dipole dipole interactions hold them together as the atoms get bigger there are more electrons so the induced dipole interactions are more powerful

Question 17

reactivity of halogens

Answer 17

decreases down the group as it gets harder for them to gain an electron

Question 18

precipitation reaction

Answer 18

a reaction in which two ionic solutions are mixed to give an insoluble compound

Question 19

precipitate

Answer 19

insoluble salt

Question 20

cations

Answer 20

positive

Question 21

anions

Answer 21

negative

Question 22

chlorine ion test

Answer 22

white AgCl precipitate forms when mixed with AgNO3, dissolves in dilute NH3

Question 23

bromide ion test

Answer 23

cream AgBr precipitate forms when mixed with AgNO3, dissolves in concentrated NH3

Question 24

iodide ion test

Answer 24

yellow AgI precipitate forms when mixed with AgNO3 does not solved

Question 25

disproportiation reactions

Answer 25

oxidation and reduction happen to the same species in the reaction

Question 26

displacement reaction

Answer 26

reaction where a more reactive halogen takes the place of a less reactive one

Question 27

halogens as oxidizing agents

Answer 27

halogens take an electron from other elements to complete their outer shell oxidizing them

Question 28

melting point trend of period 2

Answer 28

increases consistently between the 1st three elements(because they are metals and the charge increases->more electrons in the cloud and decreasing radius), big jump to silicon (because its a giant covalent structure) low temps for the last 3 because they are simple covalent structures the noble gas has the lowest temp-> has an atomic tructure

Question 29

test for NH4+

Answer 29

add sodium hydroxide NH4+ ions react with OH- ions to produce NH3 and H20 the ammonia gas will turn litmus paper blue

Question 30

test for CO3 2-

Answer 30

CO3 2- reacts with H+ ions (acids) CO2 is formed - it will turn limewater cloudy

Question 31

test for SO4 2-

Answer 31

they react with barium ions to from a white precipitate