periodic table

Question 1

s block

Answer 1

group 1 and 2
- metals that form basic oxides
-reducing agents (donate electrons to easily become cations)
-MPT decreases down the group

Question 2

p block

Answer 2

-Non metals
- form acidic oxides
-oxidising agent (easily takes electrons to become anions)
-MPT increases down the group

Question 3

d block

Answer 3

Transition metals

Question 4

oxidation

Answer 4

oxidation number in increased
(e.g Na (0) become Na (+1))
an oxidising AGENT accepts electrons (therefore being reduced itself)

Question 5

reduction

Answer 5

oxidation number goes down
(e.g. Br (0) become Br (-1))
A reducing agent DONATES electrons (therefore being oxidised)

Question 6

redox reaction

Answer 6

both oxidation and reduction occur in the same reaction
- both an oxidising and a reducing agent are present

Question 7

oxidation number rules

Answer 7

Group 1= +1
Group 2= +2
Group 6= -2
Group 7= -1
Oxygen= -2 (excluding peroxides or with fluorine)
Hydrogen= +1 (excluding hydrides)

Question 8

oxides

Answer 8

s blocks form oxides when they come into contact with oxygen
4M+O2 –> 2M2O (G1)
2M+O2 –> 2MO

Question 9

oxides with acid

Answer 9

oxides react with acid to form salt and water
e.g. 2Li2O + 2HCl —> LiCl2 + H2O

Question 10

S block with water

Answer 10

Will generally form a hydroxide and hydrogen
GROUP 1- reaction’s more intense as you go down the group
2M + 2H2O —> 2MOH + H2

Question 11

Group 2 with water

Answer 11

Berylium- no reaction
Magnesium- forms an oxide as magnesium hydroxide decomposes at high temps
REST-
M + 2H2O –> M(OH)2 +H2

Question 12

SOLUBILITY (Mg)

Answer 12

ONLY MgSO4 is soluble (magnesium sulfate)
rest form white precipiate

Question 13

SOLUBILITY (Ca)

Answer 13

CaSO4 is soluble
CaOH is sparingly soluble
CaCO3 forms white precipitate

Question 14

SOLUBILITY (Sr)

Answer 14

(all carbonates are insoluble except G1)
SrOH is soluble
SrSO4 is sparingly soluble
(SSS)

Question 15

Reactivity (G1 and 2)

Answer 15

-elements get more reactive as you go down
-electrons need to be lost
-nuclear pull is weaker so electrons are more easily lost as atoms get larger
-G1 reacts more vigorously as they only have one electron to lose

Question 16

thermal decomposition

Answer 16

caco3 –> cao + co2
thermal decomposition occurs SLOWER down a group as the element are more THERMALLY STABLE
(occurs in carbonates to form an oxide and carbon dioxide)
(also occurs in hydroxides except water is formed instead of CO2)

Question 17

solubility in groups

Answer 17

solubility of HYDROXIDES increases down a group
solubility of SULPHATES decreases down a group
solubility of carbonates (soluble for none)

Question 18

reactions with acid

Answer 18

G1 and 2 oxides and hydroxides form salt and water
strength of base is measured by how easily the elements will dissociate into ions (G1 is stronger)

Question 19

First four halogens (G7)

Answer 19

F- pale green
Cl- yellow/green
BROmine- BROwn
I- grey solid, purple gas (MLP)
-volatility (tendency to form gas) decreases down the group
-inter molecular forces get stronger as atom increases in size
-reactivity also decrease (less oxidising power)
-less attraction from larger atoms

Question 20

Halogen reactions (sodium)

Answer 20

EQUATION: 2Na + X2 —> 2NaX
X is a halogen (diatomic)
OBSERVATION: bright red flame (sodium ignites), white precipitate (all halogens are insoluble)

Question 21

Halogen reactions (iron)

Answer 21

EQUATION (Iodine)
Iodine is less reactive and can only form iron (ii) iodide
Fe +I2 —> FeI2
EQUATIONS (general)
forms iron(iii) hallide
2Fe + 3X2 –> 2FeX3
OBSERVATION- brown gas

Question 22

silver nitrate test

Answer 22

white prec- cl (prec dissolves in ammonia)
cream prec- br (slightly dissolves in NH3)
yellow prec- I (doesn’t dissolve in NH3)

Question 23

uses

Answer 23

cl- kills bacteria in water
F- strengthens tooth enamel