P BLOCK (2) 15 and 16 Flashcards

1
Q

Molecular nitrogen comprises

A

78% of atmospheric volume

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2
Q

sodium nitrate,

A

Chile saltpetre

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3
Q

potassium nitrate

A

Indian salt petre

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4
Q

Phosphorous occurs in

A

Ca9(PO4)6. CaX2
(X = F, Cl or OH)

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5
Q

arsenic, antimony, and bismuth are mainly found in

A

sulfide ores

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6
Q

trend in radius in the 15th group

A

A considerable increase from N to P. only a small increase from As to Bi

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7
Q

the trend in IE in the 15th group

A

decreases down the group

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8
Q

trend in EN in the 15th group

A

Decreases down the group. but for heavier elements, the difference is not that prominent

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9
Q

Boiling point?in 15th group

A

increases down the group

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10
Q

melting point in the 15th group?

A

increases till As then decreases to Bi

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11
Q

Bismuth hardly forms elements in which OS

A

-3

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12
Q

The only well-characterized Bi (V) compound is

A

BiF5

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13
Q

Oxidation states of Nitrogen that disproportionate in acid medium

A

+1 to +4

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14
Q

phosphorous OS that disproportionate in both acidic and alkaline medium

A

+5 to -3

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15
Q

anomalous property of N is due to

A

small size, high electronegativity, high ionization enthalpy, and non-availability of orbitals

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16
Q

why the heavier elements cannot form p pi p pi bonding

A

their atomic orbitals are so
large and diffuse that they cannot have effective overlapping

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17
Q

why is a single N–N bond weaker than a single P–P bond

A

because of the high interelectronic repulsion of the non-bonding electrons, owing to the small bond length

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18
Q

order of stability of hydrides of group 15

A

The stability of hydrides decreases from NH3 to BiH3

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19
Q

reducing character of hydrides of group 15

A

increases

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20
Q

why does ammonia have higher MP and BP?

A

because it forms hydrogen bonding

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21
Q

acidic character of oxides of group 15

A

decreases down the group

22
Q

The oxides of the type E2O3 of nitrogen and phosphorus are

A

purely acidic

23
Q

oxides of E2O3 arsenic and antimony

A

amphoteric

24
Q

oxides of E2O3 bismuth

A

predominantly basic.

25
Q

in the case of Nitrogen, which trihalide is stable

A

only NF3

26
Q

which trihalide is ionic in the case of group 15

A

BiF5

27
Q

group 15 elements react with metals in which OS

A

+3

28
Q

% of oxygen in earth’s crust

A

46.6%

29
Q

% of oxygen in the air

A

21%

30
Q

% of sulfur in the earth’s crust

A

0.03 - 0.1%

31
Q

group 16, the trend in atomic and ionic radii

A

increases down the group

32
Q

trend in ionization enthalpy of group 16

A

IE decreases down the group

33
Q

electron gain enthalpy order of group 16

A

O<S>Se>Te>Po</S>

34
Q

EN of group 16

A

decreases down the group

35
Q

allotropy is exhibited by which all elements in group 16

A

all elements exhibit allotropy

36
Q

order of MP and BP

A

increases down the group

37
Q

The large difference between the melting and boiling points of oxygen and sulfur may be explained based on?

A

their atomicity; oxygen exists as a diatomic molecule (O2) whereas sulfur exists as a polyatomic molecule (S8).

38
Q

The stability of -2 oxidation state in group 16

A

decreases down the group

39
Q

oxidation states exhibited by elements of group 16

A

+2, +4, +6

40
Q

Bonding in +4 and +6 is

A

covalent

41
Q

the effect of the absence of d orbitals in oxygen

A

limits its covalency to four and in practice, rarely exceeds two

42
Q

acidic character of hydrides of group 16

A

increases down the group

43
Q

the thermal stability of hydrides

A

decreases down the group

44
Q

selenium dioxide is a

A

solid

45
Q

the hydride without reducing property

A

water

46
Q

reducing property of oxides of group 16

A

decreases down the group

47
Q

SO2 is a ______ agent while TeO2 is a _________ agent

A

reducing agent and oxidizing agent

48
Q

both types of oxides in Group 16 are

A

acidic

49
Q

among hexahalides which one is only stable?

A

hexafluoride

50
Q

which hexa fluoride is exceptionally more stable?

A

SF6

51
Q

which all elements of group 16 form dichlorides and dibromides

A

all elements in group 16 except Oxygen

52
Q

mono halides of group 16 exist as

A

dimers