halogens Flashcards
halogens are what type of bonded?
covalently bonded
what type of substance are halogens?
simple molecular
what trends do halogens have?
- diatomic
- colours get darker down the group
- MP/ BP increases down the group
what is flourine?
a very pale yellow gas
what is chlorine?
a pale green gas
what is bromine?
a brown liquid
what is iodine?
a dark grey solid
what is astatine?
a black solid
what do halogens and metals form when they react together?
ionic compounds
halogens need to lose or gain an electron?
gain an electron to fill their outer shell
why does melting and boiling point increase as you go down the group?
- atoms have more electron shells
- the extra electron is further away from the nucleus
- its attraction to the nucleus is weaker
what is the chemical test for chlorine?
damp blue litmus paper- turns white
why does damp blue litmus paper turn white?
chlorine acts as a bleaching agent
HCL is what type of bonded and what type of substance?
covalently bonded and a simple molecular substance
why is HCL a gas?
- it has a low boiling point
- weak intermolecular forces
dissolving HCL in water?
- HCL (g) dissolves to form HCL (aq)
- HCL (aq) dissociates to form H+ (aq)
- The H+( aq) is acidic
- HCL (aq) is called hydrochloric acid
dissolving HCL in methylbenzene?
- HCL(g) dissolves to form HCL (org)
- HCL (org) cannot dissociate
- there is no H+ (org)
- HCL (org) is not acidic
what colour is chlorine (aq)?
colourless
what colour is bromine (aq)?
yellow
what colour is iodine (aq)?
brown
what colour is KCL (aq)?
colourless
what colour is KBR (aq)?
colourless
what colour is KI (aq)?
colourless
KCL + BR2?
-NO change
-STAYS yellow
KCL + I2?
-NO change
-STAYS brown
KBR + CL2?
-chlorine DISPLACES bromine
-colourless to YELLOW
KBR + I2?
-NO change
-STAYS brown
KI + CL2?
-chlorine DISPLACES iodine
-colourless to BROWN
KI + BR2?
-bromine DISPLACES iodine
-yellow to BROWN
what is the reactivity trend for chlorine, bromine and iodine?
chlorine > bromine > iodine
what is the colour change due to in salt and halogen reactions?
the halogens as salts are colourless
halogen displacement reactions are all what type of reactions?
redox reactions
