big boy group 7

Question 1

fluorine is ignored because..

Answer 1

behaves sometimes differently to the others

Question 2

astatine is ignored because

Answer 2

only exists as radioactive isotopes

Question 3

exists as

Answer 3

diatomic molecules

Question 4

group 7 melting and boiling points depend on

Answer 4

inter molecular forces of attraction between the two molecules -london forces

Question 5

trend in boiling and melting points

Answer 5

forces increase in strength down group 7 as number of electrons in the molecule increases

Question 6

physical changes

Answer 6

bromine liquid left at room temp gives of brown gas as boiling point not much higher than room temperature
iodine heated as solid goes straight to a gas-sublimation

Question 7

electronegativity

Answer 7

ability of an atom to attract a pair of electrons in a covalent bond -depend on nuclear charge,atomic radius and shielding effect of inner energy levels

Question 8

electronegativity of group 7

Answer 8

highest of any group and fluorine is the highest of all elements

Question 9

trend in reactivity

Answer 9

reactivity decrease down group 7 act mostly as oxidizing agents an d gain electrons due to electronegativity -decreases with electronegativity down the group

Question 10

reactions with group 1 and 2

Answer 10

products ionic salts that are usually white
electron transfer to the halogen
redox

Question 11

displacement reactions

Answer 11

more reactive displaces less reactive
take place in solutions see a colour change
add organic solvent like cyclohexane after reaction then shake
halogens are more soluble in cyclohexane so dissolve onto the top layer colour easier see
pale green=chlorine
organe=bromine
iodine=purple or violet
redox

Question 12

chlorine is one of the most reactive because

Answer 12

smallest atom so incoming electron get closer and more attracted by the nucleas
smallest number of complete inner energy levels so electrons experience less repulsion

Question 13

disproportionation

Answer 13

element undergoes both oxidation and reduction at the same time

Question 14

chlorine and water

Answer 14

dissolves to form chlorine water 
also reacts to from HCl (hydrochloric acid) and HCl0 (chloric (I) acidrless solutions 
Cl2+H2O=HCl+HCl0
disproportionation 
disinfects water

Question 15

chlorine with cold alkali

Answer 15

e.g cold aqueous dilute sodium hydroxide forms sodium chloride and sodium chlorate (I)
Cl2+2NaOH=NaCl+NaClO+H2O
dispro
sodium chlorate (i) disinfectant

Question 16

chlorine with a hot alkali

Answer 16

hot concentrated sodium hyrdoxide solution it reacts to form sodium chlordie and sodium chlorate (v)
dispro
3Cl2+6NAOH=5NaCl+NaCl03+3H2O
dispro
sodium chlorate (v) bleaching and weed killer
bromine and iodine simialt