inorganic chemistry and the periodic table

Question 1

why doe step ionisation energy decrease as you go down group 2?

Answer 1

each element has an extra electron shell, this means that they are further away from the nucleus and also they have more shelling meaning that it is easier to remove the outermost electrons.

Question 2

what happens to the reactivity of the elements as you go down group 2?

Answer 2

the reactivity increases as you go down the group as they usually react by losing their two outermost electrons so the lower their ionisation energies the quicker they will react.

Question 3

what do group 2 metals react with water to give?

Answer 3

metal hydroxide and hydrogen

e.g. Ca + 2H2O —> Ca(OH)2 + H2

Question 4

what happens when group 2 metals are burned in oxygen?

Answer 4

they form a solid white oxide

Question 5

what happens when group 2 metals read with chlorine?

Answer 5

they form solid white chlorides.

Question 6

what are the reactions like of group 2 oxides with water

Answer 6

they react steadily with water to form metal hydroxides, which dissolve.
beryllium is an exception, it does not react with water and it’s hydroxide is insoluble also magnesium reacts very slowly and hydroxide not very soluble - as you go down the group the y form more stronger alkaline solutions as the hydroxides are more soluble

Question 7

what are the reactions like of group 2 oxides with dilute acids

Answer 7

because they are bases they neutralise the acids forming solutions of the corresponding salts

Question 8

what are the trends ion solubility of the group 2 elements?

Answer 8

they depend in the compound Anion. generally group 2 ions that contain a single charged negative ion e.g. OH- increase in solubility as you go down the group

compounds that contain double charged negative ions such as sulphates decrease in solubility as you go down the group
barium sulfate is insoluble

Question 9

what happens to the thermal stability of carbonates and nitrates as you go down the group?

Answer 9

the thermal stability increases down a group. the carbonate and nitrate mins are largely negative ions andean be made unstable by the presence of a positively charged ion. the cation polarises the anion, distorting it, the greater the distortion the less stable the compound

large cations cause eless distorsion than smaller ones as they have a lower charge density. group two compounds are less stable than 1

Question 10

what are the colours for the flame test for the group 1 elements?

Answer 10

Li- red 
Na- orange 
Pa- lilac 
Rb- red
Cs- blue

Question 11

what are the flame colours for the group 2 elements?

Answer 11

Ca- brick-red
Mg- colourless
Sr- crimson
Ba- green

Question 12

how do you conduct a flame test?

Answer 12

mix a few drops of the compound that you are testing with a few drops of HCL, heat a piece of nichrome wire in a bunsen and then do the test.

Question 13

how do you test how quickly nitrates dissolve?

Answer 13

how long it takes for a certain amount of oxygen is produced or how long it takes for a certain amount of brown gas to form

Question 14

how do you test how quickly carbonates dissolve?

Answer 14

how long it takes for a certain amount of CO2 to be produced

Question 15

what is the trend for halogens at room temperature?

Answer 15

fluorine - pale yellow - gas
chlorine - green - gas
bromine - red brown - liquid
iodine - grey - solid

Question 16

what are the trends in halogen solubility?

Answer 16

they get less reactive as you go down the group. they usually react by gaining an electron in their outer shell this means that they are reduced and therefore they reduce another. as you go down the group the atoms become larger and so therefore they can’t attracted the electron that they require and so they therefore become less reactive

Question 17

what happens to the boiling point as you go down the group?

Answer 17

it increases. as you go down the group there is an increase in electron shells this means that the london forces between the molecules get stringer. harder to overcome the intermolecular forces and so therefore the boiling point goes up

Question 18

what happens in relations between halogen and halide ions?

Answer 18

if the halogen is more creative than the halide then the halogen will displace the halide.

Question 19

what happens between halogens and cold alkanes?

Answer 19

the Halogens undergo Disproportionation, they are simultaneously reduced and oxidised

X2 + 2NaOH –> NaOX + NaX + H2O
0 +1 -1

Question 20

how can chlorine be used for eater treatment?

Answer 20

chlorine is used to kill bacteria in water. when you mix chlorine with water it undergoes disproportionation. you end up with HCl and hypochlorus acid (HClO) this ionises to chlorate ions

Question 21

what is the disproportionation of halogens with hot alkalis

Answer 21

3X2 + 6NaOH –> NaXO3 +5NaX+ 3H2O

Question 22

what happens to the reducing power oh halides as you go down the group?

Answer 22

it increases. the bigger the atom the more shielding the further away it is from the nucleus and so the less the attraction so the easier it is to loose an electrons easily.

Question 23

explain the reactions with kF or KCL in sulphuric acid

Answer 23

hydrogen chloride or hydrogen fluoride gas is formed - misty fumes
they are not strong enough reducing agents so th reaction stops there

Question 24

explain the reactions with KBr in sulphuric acid

Answer 24

the first reaction produces HBr and gives off misty fumes. the bromine ions are strong reducing agents and so then react with the H2SO4 again in a redox reaction. this produces choking fumes of surfer dioxide and orange fumes of bromine Br2

Question 25

explain the reactions with KI in sulphuric acid

Answer 25

first reaction produces misty fumes. the iodide ions then reduce the H2SO4. the iodide is such a strong reducing agent that it goes on to further reduce the SO2 to H2S

Question 26

what is the test for halides ?

Answer 26

dilute nitric acid to remove the ions which might interfere with thereaction= and then you add silver nitrate

Question 27

what are the results of the halide test ?

Answer 27

fluoride - no reaction
chloride - white precipitate
bromide - cream precipitate
iodide - yellow precipitate

Question 28

what happens when you add ammonia after the halide test?

Answer 28

AgCl precipitate dissolves in dilute ammonia to give a colourless solution
AgBr precipitate remains unchanged in dilute ammonia however dissolves in concentrated
AgI does not dissolve in either

Question 29

describe the reaction to detect carbonates using HCl

Answer 29

with dilute Hal carbonates will fizz as they give off carbon dioxide, hsydrogencarbonates will also fizz because they give off carbon dioxide

Question 30

what is the test for sulphates

Answer 30

use HCl and Barium Chloride and f a white precipitate of barium sulphate forms then the original compound contained a sulphate

Question 31

how do you test for ammonia compounds?

Answer 31

use red litmus paper or add NaOH to the substance and then gently heat.