group 7 : Flashcards
(26 cards)
what are group 17 elements/7 elements called ?
halogens
what is the name of the group 17/7 elements (LIST 5)
flourine (F)
chlorine (Cl)
bromine (Br)
iodine (I)
astatine (At)
halogens have both have …. (in terms of boiling point and melting point)
low boiling point and melting point
what can halogens exist as ?
diatomic molecules
how many electrons does halogens have in their outer shell and what subshell ? (3)
- 7 in outer-shell
- 2 in the s-subshell + 5 in the p-subshell
- (xs2xp5)
what happens to the boiling point as you go down group 17/7 ?
the boiling point increases
what is the physical state change within group 7/17 ?
gas to liquid to solid
why does this physical state change occur in group 7/ 17 ? (2)
- as each successive element has an extra shell of electrons
- this leads to a high level of London forces
(intermolecular induced dipole dipole forces ) between the molecules .
halogens are both …. (in terms of reactivity and electronegativity )
very reactive and highly electronegative
halogens being very reactive and highly electronegative means ….
-they are very good at attracting and capturing electrons
-this means that they are strong oxidising agents
what happens in a reaction to each atom ?
it gains an electron which forms an 1- ion and obtains a noble gas configuration
what happens to the reactivity and oxidsing power of the halogens ?
they decrease moving down a group
why do the halogens decrease in reactivity and oxidising power ? (3)
- as the atomic radius increases ( the nuclear pull is further away from incoming electrons )
-the electron shielding increases - the ability to gain an electron in the p-subshell and form 1-ions decreases
how can the decrease in reactivity be shown ?
in the reactions that halogens undergo with other halide ions
where does redox reactions occur between ? (list a few with the correct state symbols )
aqueous solutions of halide ions
- Cl- (aq), Br- (aq) , I- (aq)
aqueous solutions of halogens
- Cl2 (aq) , Br2 (aq) , I2 (aq)
how does a displacement reactions work in terms of halogens ?
a more reactive halogen will oxdise and displace a halide of a less reactive halogen
what does it mean when a colour changes with halogens with different coloured solutions ?
a redox reaction must have occurred
what is the mixture usually shaken with ?
an organic solvent , cyclohexane
what colour is Cl2 in water ?
pale green
what colour is Cl2 in cyclohexane ?
pale green
what colour is Br2 in water ?
orange
what colour is Br2 in cyclohexane ?
orange
what colour is I2 in water ?
brown
what colour is I2 in cyclohexane ?
violet
