Group 7/ The halogens

Question 1

what are the properties of group 7 atoms

Answer 1

very reactive non metals
gain one electron when ionised
exist as diatomic molecules
non polar

Question 2

what is the trend in electronegativity in group 7 as u go down the group

Answer 2

Electronegativity decreases
Because : number of energy levels increases
so weaker attraction between nucleus and electrons in a covalent bond

Question 3

what is the trend in boiling point ad u go down group 7

Answer 3

increased
because side of atom increases so more electrons
more london forces between the molecules that need to be broken

Question 5

What is the appearance of fluorine at room temp

Answer 5

pale yellow
gas

Question 6

appearance of chlorine at room temps

Answer 6

pale green
gas

Question 7

appearance of bromine at room temp

Answer 7

dark red/orange
liquid

Question 8

appearcje of iodide at room temp

Answer 8

dark blue/black
solid

Question 9

What is an oxidising agent

Answer 9

electron acceptor
gained electrons
is reduced

Question 10

trend in ability of halogens to act as oxidising agents down group 7

Answer 10

decreased
they become less reactive down the group

Question 11

why do halogens become less reactive down the group

Answer 11

atomic readings increases
shielding increases
halogen atom gains an electron less easily
because there’s a weaker attraction from the nucleus

Question 12

how can halide ions be identified in solution

Answer 12

used acidified silver nitrate

Question 13

ionic equation for adding acidified silver nitrate to a halide

Answer 13

Ag+ (aq) + X- (aq) -> AgX

Question 14

What observation is made when F- is reacted with silver nitrate

Answer 14

No visible chnage (as AgF is soluble)
AgF (aq)

Question 15

Observation made when chloride ion reacts with silver nitate

Answer 15

silver halide : AgCl (s)
White ppt

Question 16

Observation when Bromide ions and reacted with silver nitste

Answer 16

silver halide : AgBr (s)
Cream ppt

Question 17

Observation between Iodide ion and silver mirage

Answer 17

silver halide : AgI (s)
yellow ppt

Question 18

what happens if carbonate and hydroxide ions are not removed

Answer 18

they will form a ppt with silver ions so they have to be removed otherwise they interfere with the test
we acidify the solution with nitric acid to remove these ions

Question 19

why can’t we use HCL to acidify the solution

Answer 19

HCL contains Cl- ions and would form a white ppt of silver chloride (AgCl(s))

Question 20

what is the trend in solubility of silver halide in ammonia down group 7

Answer 20

solubility decreases

Question 21

reaction of chlorine with water

Answer 21

Cl2(g) + H2O(l) —\ HCl(aq) + HClO(aq)
\—
equilibrium

Question 22

what is disproportionation

Answer 22

oxidation and reduction of the same element

Question 23

how should we use chlorine

Answer 23

is very small amounts because it’s toxic

Question 24

reaction between chlorine and NaOH

Answer 24

Cl2 + 2NaOH -> H2O + NaCl + NaClO

Question 25

how do you test for carbonate ions

Answer 25

carbonate ions release CO2 and water when reacted with an acid **add dilute nitric acid and test the gas protected with limewater**

Question 26

result for test dir carbonate ions

Answer 26

effervescence and gas produced (CO2) will turn the lime water cloudy

Question 27

test for sulfate ions

Answer 27

make a solution of the compound add some acidified barium nitrate solution

Question 28

result for test for sukfate ions

Answer 28

white ppt of BaSO4

Question 29

test for chlorine ions with acidified silver notate

Answer 29

white ppt