physical and chemical properties Flashcards

1
Q

Be is not considered as alkaline earth metal as

A

BeO is amphoteric

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2
Q

which alkaline earth metal doesn’t form alkaline oxide

A

Be

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3
Q

Li
flame color

A

crimson red

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4
Q

Na
flame color

A

golden yellow

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5
Q

K
flame color

A

lilac violet

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6
Q

Rb
flame color

A

red violet

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7
Q

Cs
flame color

A

blue

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8
Q

Be
flame color

A

no color

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9
Q

Mg
flame color

A

no color

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10
Q

Ca
flame color

A

brick red

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11
Q

Sr
flame color

A

crimson red

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12
Q

Ba
flame color

A

apple green

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13
Q

hottest part of flame is

A

mid portion

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14
Q

which metals don’t give flame test

A

Be and Mg

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15
Q

ionization energy order
alkali metals
group 1

A

Li > Na > K > Rb > Cs

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16
Q

hydration energy order
alkali metals
group 1

A

Li > Na > K > Rb > Cs

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17
Q

melting point order
alkali metals
group 1

A

Li < Na < K < Rb < Cs

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18
Q

boiling point order
alkali metals
group 1

A

Li < Na < K < Rb < Cs

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19
Q

density order
alkali metals group 1

A

Li < K < Na < Rb < Cs

Na and K switch

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20
Q

most negative SRP in grp 1

A

Li

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21
Q

least negative SRP in grp 1

A

Na

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22
Q

most abundant alkali metal

A

Na

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23
Q

ionisation energy order
alkaline earth metals
group 2

A

Be > Mg > Ca > Sr > Ra > Ba

Ra and Ba switch

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24
Q

hydration energy order
alkaline earth metals
group 2

A

Be > Mg > Ca > Sr > Ba > Ra

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25
Q

melting point order
alkaline earth metals
group 2

A

Be > Ca > Sr > Ba > Mg

Mg at last

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26
Q

boiling point order
alkaline earth metals
group 2

A

Be > Ba > Ca > Sr > Mg

Mg and Ba switch

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27
Q

most abundant alkaline earth metal

A

Ca

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28
Q

density order
group 2

A

Ca < Mg < Be < Sr < Ba

Be and Ca switch

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29
Q

hardest alkali metal

A

Li

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30
Q

alkali metals used in photoelectric cell

A

Cs and K
they have low IP so show photoelectric effect

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31
Q

which are harder
grp1 or grp2 metals

A

alkaline earth metals are more harder than alkali metals
grp2 > grp1

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32
Q

wavelength of flame color of alkali metals

A

Li 670.8
Na 589.2
K 766.5
Rb 780
Cs 455.5

Rb > K > Li > Na > Cs

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33
Q

pure oxides and peroxide of alkali metals color

A

colorless

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34
Q

peroxide and superoxide
para/di magnetic

A

peroxide - dimagnetic
superoxide - paramagnetic

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35
Q

peroxides of alkaline earth are colored due to

A

lattice effect

36
Q

Be when burnt in air

A

BeO and Be3N2
burn brilliantly

37
Q

Mg when burnt in air

A

MgO and Mg3N2
burn with dazzling brilliance

38
Q

BeO and MgO are used as
and why

A

used as refractory
as have high mpt

39
Q

Ba + O2 –>

A

BaO2

40
Q

alkali metals forming oxide/peroxide/superoxides

A

Li oxide(Li2O)
Na oxide(Na2O) peroxide(Na2O2)
K superoxide(KO2)
Rb superoxide(RbO2)
Cs superoxide(CsO2)

41
Q

superoxides are formed by which alkali metals

A

K, Rb and Cs

42
Q

KO2, RbO2, CsO2 color
(superoxides)

A

orange/yellow crystalline

43
Q

which alkaline earth metals form peroxide

A

Ba and Sr

44
Q

which alkali metals reacts with N2 at room temperature

A

Li
Li3N

45
Q

stability order
oxide / peroxide / superoxide

A

oxide > peroxide > superoxide
reason: lattice energy effect

46
Q

alkali metals reaction with water

A

M + H2O –> MOH + H2

47
Q

reactivity of alkali metals with water

A

Li slowly
Na quickly
K, Rb, Cs vigorously

48
Q

alkali metals react with proton donors like ____ to liberate H2

A

alcohol
gaseous ammonia
terminal alkyne

49
Q

Na + NH3 –>

A

NaNH2 + H2
(soda amide)

50
Q

NaNH2

A

soda amide

51
Q

M + ROH –>

A

ROM + H2

52
Q

alkaline earth metal reaction with water

A

M + H2O –> M(OH)2 + H2

53
Q

Be + H2O –>

A

no rxn
low oxidation potential of Be

54
Q

Mg + H2O –>

A

boiling water
MgO + H2

55
Q

Ca/Sr/Ba + H2O –>

A

M(OH)2 + H2

56
Q

M + H2 –>

A

MH (grp1)
MH2 (grp2) (except Be)

57
Q

which alkaline earth metals don’t form hydride directly on heating with H2

A

Be
BeCl2 + LiAlH4 –> BeH2 + LiCl + AlCl3

58
Q

BeCl2 + LiAlH4 –>

A

BeH2 + LiCl + AlCl3

59
Q

covalent hydride of alkaline earth metals

A

BeH2 and MgH2

60
Q

MH + H2O –>
alkali metals

A

MOH + H2

61
Q

M + X2 –>

A

2MX (alkali metals)
MX2 (alkaline earth metals)

62
Q

order of reactivity for halogens
alkali metals

A

Cl2 / Br2/ I2
Li < Na < K < Rb < Cs

F2
Li > Na > K > Rb > Cs

63
Q

best way to prepare BeF2

A

thermal decomposition of (NH4)BeF2

64
Q

preparation of BeCl2

A

BeO + C + Cl –> BeCl2 + CO

65
Q

all halide of alkaline earth metals are ionic except

A

beryllium halides
reason: small size and high effective nuclear charge

66
Q

BeCl2 structure in solid and vapour phase

A

in solid phase, it has a chain structure

in vapour phase, tends to form chloro-bridged dimer

67
Q

alkali metals
M2O + H2O –>
oxide

A

MOH

68
Q

alkali metals
M2O2 + H2O –>
peroxide

A

MOH + H2O2

69
Q

alkali metals
MO2 + H2O –>
superoxide

A

MOH + H2O2 + O2

70
Q

thermal stability / solubility in water of hydroxides

A

LiOH < NaOH < KOH < RbOH < CsOH
Be(OH)2 < Mg(OH)2 < Ca(OH)2 < Sr(OH)2 < Ba(OH)2

71
Q

amphoteric hydroxide of s block metal

A

Be(OH)2

72
Q

which alkali earth hydroxide dissolve in alkali

A

none

73
Q

LiHCO3 doesn’t exist due to

A

high polarizing power of Li+
uncomparable size of Li+ ang HCO3-

74
Q

how crystalline structure of NaHCO3 and KHCO3 shows H bonding

A

in NaHCO3, HCO3- are linked to infinite chain
in KHCO3, RbHCO3, CsHCO3, HCO3- forms dimeric anion

75
Q

solubility of carbonate
solubility of hydroxides
solubility of sulphates

A

carbonates - decreases down the group
hydroxides - increases down the group
sulphates -
~ grp1 - increases down the group
~ grp2 - decreases down the group

76
Q

amalgamation

A

alkali and alkaline earth metal get dissolved in mercury to form amalgam
highly exothermic

77
Q

alkali metals
M2SO4 + C –>

alkaline earth metals
MSO4 + C –>

A

M2S + CO

MS + CO2

78
Q

decomposition of alkali metals nitride

A

MNO3 –> MNO2 + O2
LiNO3 –> Li2O + NO2 + O2
NaNO3 -(800C)–> Na2O + N2 + O2

79
Q

Li3N + H2O –>
Be3N2 + H2O –>

A

LiOH + NH3
Be(OH)2 + NH3

80
Q

decomposition of alkaline earth metals nitride

A

M(NO3)2 –> MO + NO2 + O2

81
Q

Li + C –>
heat

A

Li2C2
ionic lithium carbide
other don’t react with carbon directly but form carbide with ethyne

82
Q

Na + C2H2 –>

A

NaH + C2 –> Na2C2

83
Q

alkaline earth metal carbides types

A
  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
Q

SiC and B4C

A

SiC - carborandum
B4C - norbia
harder than diamond
covalent carbide

85
Q

carbides of ______ are hydrolysed by water or dil acids

A

Cr, Mn, Fe, Co, Ni