inorganic chemistry and the periodic table Flashcards Preview

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Flashcards in inorganic chemistry and the periodic table Deck (42)
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1

group 7 name
characteristics

halogens
diatomic molecules

2

Why are fluorine and astatine generally ignored out of the halogens?

Fluorine behaves differently to rest of elements and astatine only exists as a radioactive isotope

3

trend in state down group 7

gas to solid

4

trend in mp/bp down group 7

increases

5

trend in electronegativities down group 7

decreases

6

how London forces are formed between diatomic halogen molecules

identical atoms mean pair of electrons are shared equally between (therefore on average aren't polar). fluctuations in charge result in a temporary dipole. if molecule on left forms an instantaneous dipole, another dipole is induced on right, producing a force of attraction (instantaneous dipole-induced dipole attraction).

7

trend in bond strength between atoms in group 7

increases as number of electrons in molecules increases

8

properties determining electronegativity of an atom

nuclear charge
distance between nucleus and bonding pair
shielding effect

9

trend in reactivity down group 7

decreases down group w electronegativity

10

roles of halogens in reactions

act as oxidising agents, gaining electrons to form a negative ion.
due to high electronegativity

11

most vigorous reactions between group 1 and 2 metals with halogens

elements at bottom of groups 1 and 2 with elements at top of group 7

12

products of group 1 and 2 metals w halogens
reaction process

salts
ionic salts that are usually white
redox reactions in which halogen acts as oxidising agent

13

oxidation numbers in reaction between group 1 and 2 metals w halogens

halogen decreases from 0 to -1
metal increases from 0 to +1/+2

14

way to make halide colors more distinctive

add an organic solvent such as cyclohexane as halogens are more soluble than in water so will dissolve in upper layer where colors will be more distinctive

15

color of chlorine / bromine/ iodine

Cl>> green
Br>> orange brown
I >> purple

16

why is chlorine most reactive of halogens?

atom is smaller so outer electrons are closer to nucleus
smallest amount of shells and so shielding is reduced

17

disproportionation

a reaction in which one element undergoes both oxidation and reduction simultaneously.

18

reaction of chlorine with water

forms chloric acid and hydrochloric acid
Cl2 +H2O >> HCl + HCLO

19

reaction of chlorine with cold alkali

forms salts of the chloric and hydrochloric acids
sodium chloride and sodium chlorate 1
eg, 2NaOH + Cl2 >> NaCl + NaClO + H2O

20

sodium chlorate use

disinfectant, used as main ingredient of bleach.

21

reaction of chlorine with hot alkali

forms salts of chloride and chlorate 5
eg, 6NaOH + 3Cl2 >> 5NaCl + NaClO3 + 3H2O

22

how do halide ions differ from halogen molecules in their reactions

halide ions act as reducing agents in reactions while halogen molecules act as oxidising agents.

23

reducing power of halide ions as you go down the group

increases

24

oxidising power of halogen molecules as you go down the group

decreases

25

sulfuric acid role in reactions

can act as an oxidising agent and an acid
partially ionising : H2SO4 >> H+ + HSO4
HSO4- >> H+ + SO42-

26

3 possible reaction products with sulfuric acid

sulfur dioxide
sulfur
hydrogen sulfide

27

observation and products in reaction of NaCl w conc. H2SO4

misty fumes and hydrogen chloride is formed

28

observation and products in reaction of NaBr w conc. H2SO4

misty fumes, brown fumes and colourless gas w choking smell
HBr, Br2, SO2

29

observation and products in reaction of NaI w conc. H2SO4

misty fumes, purple fumes/black solid, colourless gas w choking smell, yellow solid, colourless eggy gas
HI, I2, SO2, S, H2S

30

role of sulfuric acid in halogen reactions

NaCl>> behaves as an acid as Cl has low reducing power
NaBr>> is reduced as Br has more reducing power
NaI >> greater reducing power of iodide ions reduces sulfuric acid fully