physical and chemical properties Flashcards
(85 cards)
1
Q
Be is not considered as alkaline earth metal as
A
BeO is amphoteric
2
Q
which alkaline earth metal doesn’t form alkaline oxide
A
Be
3
Q
Li
flame color
A
crimson red
4
Q
Na
flame color
A
golden yellow
5
Q
K
flame color
A
lilac violet
6
Q
Rb
flame color
A
red violet
7
Q
Cs
flame color
A
blue
8
Q
Be
flame color
A
no color
9
Q
Mg
flame color
A
no color
10
Q
Ca
flame color
A
brick red
11
Q
Sr
flame color
A
crimson red
12
Q
Ba
flame color
A
apple green
13
Q
hottest part of flame is
A
mid portion
14
Q
which metals don’t give flame test
A
Be and Mg
15
Q
ionization energy order
alkali metals
group 1
A
Li > Na > K > Rb > Cs
16
Q
hydration energy order
alkali metals
group 1
A
Li > Na > K > Rb > Cs
17
Q
melting point order
alkali metals
group 1
A
Li < Na < K < Rb < Cs
18
Q
boiling point order
alkali metals
group 1
A
Li < Na < K < Rb < Cs
19
Q
density order
alkali metals group 1
A
Li < K < Na < Rb < Cs
Na and K switch
20
Q
most negative SRP in grp 1
A
Li
21
Q
least negative SRP in grp 1
A
Na
22
Q
most abundant alkali metal
A
Na
23
Q
ionisation energy order
alkaline earth metals
group 2
A
Be > Mg > Ca > Sr > Ra > Ba
Ra and Ba switch
24
Q
hydration energy order
alkaline earth metals
group 2
A
Be > Mg > Ca > Sr > Ba > Ra
25
melting point order
alkaline earth metals
group 2
Be > Ca > Sr > Ba > Mg
Mg at last
26
boiling point order
alkaline earth metals
group 2
Be > Ba > Ca > Sr > Mg
Mg and Ba switch
27
most abundant alkaline earth metal
Ca
28
density order
group 2
Ca < Mg < Be < Sr < Ba
Be and Ca switch
29
hardest alkali metal
Li
30
alkali metals used in photoelectric cell
Cs and K
they have low IP so show photoelectric effect
31
which are harder
grp1 or grp2 metals
alkaline earth metals are more harder than alkali metals
grp2 > grp1
32
wavelength of flame color of alkali metals
Li 670.8
Na 589.2
K 766.5
Rb 780
Cs 455.5
Rb > K > Li > Na > Cs
33
pure oxides and peroxide of alkali metals color
colorless
34
peroxide and superoxide
para/di magnetic
peroxide - dimagnetic
superoxide - paramagnetic
35
peroxides of alkaline earth are colored due to
lattice effect
36
Be when burnt in air
BeO and Be3N2
burn brilliantly
37
Mg when burnt in air
MgO and Mg3N2
burn with dazzling brilliance
38
BeO and MgO are used as
and why
used as refractory
as have high mpt
39
Ba + O2 -->
BaO2
40
alkali metals forming oxide/peroxide/superoxides
Li oxide(Li2O)
Na oxide(Na2O) peroxide(Na2O2)
K superoxide(KO2)
Rb superoxide(RbO2)
Cs superoxide(CsO2)
41
superoxides are formed by which alkali metals
K, Rb and Cs
42
KO2, RbO2, CsO2 color
(superoxides)
orange/yellow crystalline
43
which alkaline earth metals form peroxide
Ba and Sr
44
which alkali metals reacts with N2 at room temperature
Li
Li3N
45
stability order
oxide / peroxide / superoxide
oxide > peroxide > superoxide
reason: lattice energy effect
46
alkali metals reaction with water
M + H2O --> MOH + H2
47
reactivity of alkali metals with water
Li slowly
Na quickly
K, Rb, Cs vigorously
48
alkali metals react with proton donors like ____ to liberate H2
alcohol
gaseous ammonia
terminal alkyne
49
Na + NH3 -->
NaNH2 + H2
(soda amide)
50
NaNH2
soda amide
51
M + ROH -->
ROM + H2
52
alkaline earth metal reaction with water
M + H2O --> M(OH)2 + H2
53
Be + H2O -->
no rxn
low oxidation potential of Be
54
Mg + H2O -->
boiling water
MgO + H2
55
Ca/Sr/Ba + H2O -->
M(OH)2 + H2
56
M + H2 -->
MH (grp1)
MH2 (grp2) (except Be)
57
which alkaline earth metals don't form hydride directly on heating with H2
Be
BeCl2 + LiAlH4 --> BeH2 + LiCl + AlCl3
58
BeCl2 + LiAlH4 -->
BeH2 + LiCl + AlCl3
59
covalent hydride of alkaline earth metals
BeH2 and MgH2
60
MH + H2O -->
alkali metals
MOH + H2
61
M + X2 -->
2MX (alkali metals)
MX2 (alkaline earth metals)
62
order of reactivity for halogens
alkali metals
Cl2 / Br2/ I2
Li < Na < K < Rb < Cs
F2
Li > Na > K > Rb > Cs
63
best way to prepare BeF2
thermal decomposition of (NH4)BeF2
64
preparation of BeCl2
BeO + C + Cl --> BeCl2 + CO
65
all halide of alkaline earth metals are ionic except
beryllium halides
reason: small size and high effective nuclear charge
66
BeCl2 structure in solid and vapour phase
in solid phase, it has a chain structure
in vapour phase, tends to form chloro-bridged dimer
67
alkali metals
M2O + H2O -->
oxide
MOH
68
alkali metals
M2O2 + H2O -->
peroxide
MOH + H2O2
69
alkali metals
MO2 + H2O -->
superoxide
MOH + H2O2 + O2
70
thermal stability / solubility in water of hydroxides
LiOH < NaOH < KOH < RbOH < CsOH
Be(OH)2 < Mg(OH)2 < Ca(OH)2 < Sr(OH)2 < Ba(OH)2
71
amphoteric hydroxide of s block metal
Be(OH)2
72
which alkali earth hydroxide dissolve in alkali
none
73
LiHCO3 doesn't exist due to
high polarizing power of Li+
uncomparable size of Li+ ang HCO3-
74
how crystalline structure of NaHCO3 and KHCO3 shows H bonding
in NaHCO3, HCO3- are linked to infinite chain
in KHCO3, RbHCO3, CsHCO3, HCO3- forms dimeric anion
75
solubility of carbonate
solubility of hydroxides
solubility of sulphates
carbonates - decreases down the group
hydroxides - increases down the group
sulphates -
~ grp1 - increases down the group
~ grp2 - decreases down the group
76
amalgamation
alkali and alkaline earth metal get dissolved in mercury to form amalgam
highly exothermic
77
alkali metals
M2SO4 + C -->
alkaline earth metals
MSO4 + C -->
M2S + CO
MS + CO2
78
decomposition of alkali metals nitride
MNO3 --> MNO2 + O2
LiNO3 --> Li2O + NO2 + O2
NaNO3 -(800C)--> Na2O + N2 + O2
79
Li3N + H2O -->
Be3N2 + H2O -->
LiOH + NH3
Be(OH)2 + NH3
80
decomposition of alkaline earth metals nitride
M(NO3)2 --> MO + NO2 + O2
81
Li + C -->
heat
Li2C2
ionic lithium carbide
other don't react with carbon directly but form carbide with ethyne
82
Na + C2H2 -->
NaH + C2 --> Na2C2
83
alkaline earth metal carbides types
1. ionic carbide
-by s block metals and Al
(a) methanide: give CH4
Al4C3 + H2O --> Al(OH)3 + CH4
Be2C + H2O --> Be(OH)2 + CH4
(b) acetylide: give C2H2
CaC2 + H2O --> Ca(OH)2 + C2H2
Al2(C2)3 + H2O --> Al(OH)3 + C2H2
SrC2 + H2O --> Sr(OH)2 + C2H2
(c) allilyde: give propyne
Mg2C3 + H2O --> Mg(OH)2+ propyne
2. covalent carbide
- SiC (carborandum)
- B4C (norbia)
3. interstitial carbide
- formed by transition metal and some lanthanides/actinides
- very hard and high melting point
84
SiC and B4C
SiC - carborandum
B4C - norbia
harder than diamond
covalent carbide
85
carbides of ______ are hydrolysed by water or dil acids
Cr, Mn, Fe, Co, Ni
