s-block Flashcards
Write the products of Li with Oxygen gas
Li2O
Write the products of Na with Oxygen gas
Na2O
Na2O2 (excess oxygen)
Write the products of K with Oxygen gas
K2O
K2O2
KO2
Write the products of Rb with Oxygen gas
Rb2O
Rb2O2
RbO2
Write the products of Cs with Oxygen gas
Cs2O
Cs2O2
CsO2
What’s the only element that reacts with nitrogen gas in first group?
Li
Write the reactions of Li with N2 gas
Li —> Li3N
Li3N +3H20 —> 3LiOH + NH3
How do 1st group elements react with hydrogen gas?
Li –> LiH
Na –> NaH
K –> KH
Cs – CsH
Rb –> RbH
What’s the nature of group 1 hydrides?
Ionic
How do group 1 hydrides react w water?
They react vigorously
NaH + H2O –> NaOH + H2
Write the reactions of group 1 metals with cold water?
Na + H20 —> NaOH + H2
Write the nature of the reactions of group1 metals reacting w cold water
Li –> Gently
Na –> Vigorously
K –> Vigorously w/ ignition
Rb/Cs –> Explosively
Na, K, Rb, Cs show exothermic reactions
How do the group 1 oxides react with water?
Li2O + H2O –> LiOH
Na2O + H20 –> NaOH
K2O + H2O –> KOH
Explain the variation of the base strength of first group metals down the group
increases
What’s the reaction of group 1 peroxides w water?
Na2O2 + H2O –> NaOH + H2O2
What’s the reaction of 1st group superoxide w water?
KO2 + H2O –> KOH + H202 + O2
Describe the reaction of acids with group 1 metals
Forms the salt and hydrogen gas
Na + HCl —> NaCl + H2
Li + H2SO4 –> Na2SO4 + H2
Describe the reactions of group 1 metal hydroxides with CO2
NaOH + CO2 –> Na2CO3 + H2O
Na2CO3 + CO2 + H20 –> NaHCO3
Write the products of Be with oxygen gas
BeO
Write the products of Mg with oxygen gas
MgO
Write the products of Ca with oxygen gas
CaO
Write the products of Sr with oxygen gas
SrO
Write the products of Ba with oxygen gas
BaO
BaO2
Write the reactions of group 2 elements with nitrogen gas
M + N2 —> M3N2 (yellow)
M3N2 + H20 –> M(OH)2 + NH3
Which group 2 element doesn’t react with Hydrogen gas?
Be
Do all group 2 elements react w hydrogen gas?
No. Be doesn’t
Write the products of group 2 metals reacting w hydrogen gas
Mg + H2 –> MgH2 ( at high pressure)
Ca + H2 –> CaH2 (at high temp.)
Sr + H2 –> SrH2 (at high temp.)
Ba + H2 –> BaH2 (at high temp.)
Then: CaH2 + H20 –> Ca(OH)2 + 2H2 (not
violent as group 1)
Write the nature of the group 2 metallic hydrides
They’re all ionic solids.
Ionic character increases down the group
Describe the reactivity of Be with water
Be doesn’t react with room temperature water, cold water or hot water
It reacts with steam as:
Be + H2O –> BeO + H2
Describe the reactivity of Mg with water
Doesn’t react with cold water or room temperature water
Reacts SLOWLY with hot water
Mg + 2H2O —> Mg(OH)2 + H2
Reacts with steam
Describe the reactivity of Ca/Sr/Ba with water
Readily reacts with water
Ca + H20 –> Ca(OH)2 + H2
Reacts with steam
How does reactivity of group 2 metals with water vary?
it increases down the group
Write reactions of group 2 metals with dilute acids
Do not act as oxidizing agents
Mg + HCl –> MgCl + H2
Write reactions of group 2 metals with concentrated acids
They show oxidizing properties with H2SO4 and HNO2
Mg + H2SO4 –> MgSO4 + SO2 + 2H20
Mg + HNO3 –> Mg(NO3)2 + NO2 + H20
They don’t show oxidizing properties w HCl
Mg + HCl –> MgCl + H2
How do group 1 hydroxides decompose?
LiOH —> Li2O + H2O
NaOH –> do not decompose
KOH –> do not decompose
RbOH –> do not decompose
How do group 2 hydroxides decompose?
Be(OH)2 –> BeO + H2O
Mg(OH)2 –> MgO + H2O
Ca(OH)2 –> CaO + H2O
Sr(OH)2 –> SrO + H2O
Ba(OH)2 –> BaO + H20
What’s the only group 1 hydroxide that decomposes?
LiOH
How do group 1 carbonates decompose?
Li2CO3 –> Li2O + CO2
Na2CO3 –> do not decompose
K2CO3 –> do not decompose
Rb2CO3 –> do not decompose
Cs2CO3 –> do not decompose
What’s the only group 1 carbonate that can decompose?
Li2CO3
How do group 2 carbonates decompose?
BeCO3 –> BeO + CO2
MgCO3 –> MgO + CO2
CaCO3 –> CaO + CO2
SrCO3 –> SrO + CO2
BaCO3 –> BaO + CO2
Describe the physical nature of group 1 bicarbonates
LiHCO3 –> Aqueous solution
NaHCO3 –> solid
KHCO3 –> solid
RBHCO3 –> solid
Describe the decomposition of bicarbonates of group 1
LiHCO3 —> Li2CO3 + CO2 + H20
NaHCO3 —> Na2CO3 + CO2 + H20
Li2CO3 is a water insoluble white precipitate
The rest of the carbonates are water soluble solids
Describe the physical nature of the carbonates of group 1
Li2CO3 is a water insoluble white precipitate
The rest of the carbonates are water soluble solids
Describe the physical nature of the carbonates of group 2
They are all water insoluble precipitates
Describe the decomposition of bicarbonates of group 2
Be(HCO3)2 —> BeCO3 + CO2 + H20
Describe the physical nature of group 2 bicarbonates
They are aqueous solutions
Describe the decomposition of group 1 nitrates
LiNO3 –> Li2O + NO2 + O2
(reddish brown NO2 evolves)
NaNO3 —> NaNO2 + O2
KNO3 —> KNO3 + O2
RbNO3 —> RBNO3 + O2
Describe the decomposition of group 2 nitrates
Be(NO3)2 —> BeO + NO2 + O2
What are s block elements?
elements which fill the last electron to a s-subshell
Give alternate names for group I and group II elements
Group I –> alkali metals
Group II –> alkali earth metals
Metallic character of s block elements
H is a non-metal
The rest are metals
common electronic configuration of group 1
ns1
Which group 1 elements do not reach a stable octet?
H and Li
Valency of group 1
always 1
Oxidation state of group 1
+1 and 0 (H can also have -1)
Natural resources containing group 1 metals
NaCl - rock salt
Na2B4O7. 10.H2O —> borax (primary standard substance)
KCl - sylvite
KCl. MgCl2. 6H2O - Carnallite
metallic character of group 11 elements
all are metals
Be is an amphoteric metal
valency and oxidation no.
+2
natural sources containing group II elements
CaCO3 - calcite. limestone
MgCO3 - magnesite
CaCO3. MgCO3 - dolomite
KCl. MgCl2. 6H2O - Carnallite
CaSO4. 2H2O - Gypsum
3Ca3(PO4)2. CaF2 - Fluroapatite
3Ca3(PO4)2. CaCl2 - Chlorapatite
color of Li with flame test
Crimson red
color of Na with flame test
Yellow
color of K with flame test
Lilac / violet
color of Rb with flame test
Red-violet
color of Cs with flame test
Blue - violet
color of Mg with flame test
-
color of Be with flame test
-
color of Ca with flame test
orange red
color of Sr with flame test
crimson red
color of ba with flame test
yellowish green