halogens Flashcards
1
Q
halogens
A
- Highly reactive nonmetals’ of group 7
- electronegativity increases up the group
- covalent diatomic molecules which are nonpolar so have low solubility in water
- dissolves easily in organic compounds like hexane
2
Q
fluorine
A
-pale yellow gas at room temp
3
Q
chlorine
A
- green as a gas
- colourless when in water or hexane
4
Q
bromine
A
- red/brown liquid
- yellow/orange in water
- orange/red in hexane
5
Q
iodine
A
- grey as a solid
- brown in water
- pink/violet in hexane
6
Q
they’re less reactive down the group
A
- usually react by gaining an electron in their outer P shell = reduced
- as they’re reduced they oxidizes another substance = oxidising agent
- as you go down the atoms become larger as the outer electron is further away from the nucleus
- outer electrons are shielded more from attraction of the positive nucleus so there’s more inner electrons so its harder for larger atoms to attract the electrons needed to form an ion
7
Q
Electronegativity
A
- measure of how well an atom attracts electrons in a covalent bond
- it decreases down the group due to an increase of the number of inner electron shells and the increase in distance between nucleus and the bonding electrons
8
Q
M + Bp
A
- Increase down the group
- there’s an increase in electron shells so london forces get stronger so it’s harder to overcome the intermolecular forces
9
Q
displacement reaction
A
- types of reaction where one element replaces another element
- Cl2 + 2KBr arrow 2KCl + Br2
10
Q
Cl2 displaces
A
- Bromide
- iodide
11
Q
Br2 displaces
A
-iodide
12
Q
I2 displaces
A
-no displacement
13
Q
bromide displaced and bromine fromed
A
-turns orange
14
Q
iodide displaced and iodine formed
A
-turns brown
