classification of elements Flashcards
(185 cards)
1
Q
how many elements are discovered
A
118
2
Q
how many elements have been discovered
A
118
3
Q
how many elements are naturally occurring
A
92
4
Q
how many elements are man made
A
26
5
Q
what was the dobereiner’s law of triads
A
it states that when chemically similar elements are placed in the increasing order of ther atomic masses in groups of three then the arithmetic mean of the 1st and 3rd element is equal to that of the 2nd
6
Q
give examples of law of triads
A
Li, Na, K, Ca, Sr, Ba, Cl, Br, I
7
Q
who was the first scientist to state that the properties of elements depended upon their atomic masses
A
dobereiner
8
Q
what was the Newlands law of octaves
A
when elements are arranged in the increasing order of their atomic masses, properties lf 1st elements are similar to the 8th as in an octave of music,
9
Q
limitations of newlands law of octaves
A
only spplicable up to calcium
10
Q
who gave the telluric helix
A
de chan courtois
11
Q
describe the lothar meyer curve
A
it is a curve between atomic weight and atomic volume
12
Q
in lothar meyer curve, where are alkali metals found
A
at peak of curve
13
Q
in lothar meyer curve, where are alkali earth metals found
A
descending limb
14
Q
in lothar meyer curve,where are halogend found
A
ascending limb
15
Q
in lothar meyer curve,where are transitional elements found
A
at bottom
16
Q
mendeleev’s periodic law
A
properties of elements are periodic functions of their atomic masses
17
Q
how many elements were in mendeleev’s periodic table
A
63 elements
18
Q
no. lf periods in mendeleev’s periodic table
A
7
19
Q
no. of periods in mendeleev’s periodic table before 1898, after 2898
A
before 8, after 9
20
Q
vacant spaces left as eka-aluminium, eka boron, eka silicon were found to be
A
scandium,gallium, germanium respectively
21
Q
mendeleev’s periodic table changed the atlmic weight of be from 13.5 to
A
9
22
Q
limitations of newlands law of octaves
A
position of H, Position of isotopes
23
Q
state the modern periodic law
A
properties of elements are periodic functions of their atomic numbers
24
Q
who gave the modern period law
A
henry mosely
25
how many period does modern period table have
7
26
how many groups does the modern periodic table have
18
27
elements with similar valench shell configuration are placed in the same
group
28
each period corresponds to the highest
principal quantum number of the elements of that period
29
shortest periods
1st, 2nd
30
longest period
6th and 7th
31
incomplete period
7th period
32
longest group
3rd group
33
group 1 is called
alkali metals
34
group 2 is called
alkali earth metals
35
group 15 is called
pnictogens/picogens
36
group 16 is called
chalcogens
37
group 17 is called
halogens
38
group 18 is called
inert gases/zero group
39
representatives elements
s and p block
40
transition elements are
d block
41
transition elements exception
Cu,Zn,Cd,Hg
42
what block acts as a bridge of 2nd period
d block
43
what are transuranic elements
elements fter U-92
44
rare earth metals
lanthanoids
45
noble metals
Au/Ag/Cu/Pt
46
outermost electronic configuration of s block
ns1-2
47
outermost electronic configuration of p block
ns2, np1-6( except He-1s2
48
outermost electronic configuration of d block
(n-1)d1-10 ns1-2
49
outermost electronic configuration of f block
(n-1)f1-14 (n-1)d0-1 ns2
50
IUPAC name of Unu
Mendelevium
51
IUPAC name of unb
nobelium
52
IUPAC name of unt
Lawrenium
53
IUPAC name of unq
Rutherfordium
54
IUPAC name of unp
dubnium
55
IUPAC name of unh
seaborgium
56
IUPAC name of uns
bohrium
57
element with no neutron
H
58
all elements are metals in s block except
H
59
all gaseous elements are in p block except
H
60
no of metals
90
61
no. of metalloids
6-8
62
metalloids
Si,Ge,Sb,At,As,Po,Te, (B)
63
no of non metals
15-16
64
amphoteric metalloid
Si
65
amphoteric metal
Be,Zn,Al,Sn,Pb
66
what is effective nuclear charge
neta attraction force experienced by the outermost electron to the nucleus
67
what is shielding effect
net Repulsive force experienced by the outer most e and inner most e
68
proportionality of zeff with m
Directly proportional
69
in period zeff
increases
70
in group zeff is
constant
71
in period SE
increases slowly
72
in group SE
increases rapidly
73
why do properties repeat
due to similar outermost EC(magic no.)
74
what is atomic radius
average distance b/w nucleus and outermost shell
75
what is atomic radius expressesd i
Angstrom or Picometer
76
what is atomic radius determined by
x ray diffraction and spectroscopic methods
77
types of atomiv radii
covalent,ionic,vander waals, metallic
78
inert gases have only
van der waal radius
79
describe the length of atomic radii
vander waal>metallic>covalent
80
if no of orbits increases, atomic radius will
increase
81
if zeff inreases, atomic radius will
decreases
82
if shielding effect increases atomic radius will
increases
83
if electronegativity difference increases
atomic radius will
decreases
84
if multiplicity kf bonds increases atomic radius will
decreases
85
due to lanthanide contraction atomic radius will
decreases
86
due to transition contraction atomic radius will
decreases
87
variation of atomic radius in period
decreases (zeff increases)
88
trend of atomic radius in 1st period
H
89
trend of atomic radius in 2nd period
Ne>Li>Be>B>C>N>O>F
90
trend of atomic radius in 4th period
Sc>Ti>Zn>Cr=Mn=V>Cu>Fe>Co>Ni
91
in group atomic radius
increases
92
in group atomic radius
increases
93
trend of atomic radius in 1st group
Li
94
trend of atomic radius in 1st group
Li)>Na>K>Rb>Cs
95
trend of atomic radius in p block
B
96
trend of atomic radius in D block
Sc>Y=La, Ti>Zn=Rf,V>Nb=Ta,Cr>Mo=W
97
order of shielding effect of orbitals
ns>np>nd>nf
98
Ionic radii
effective distance b/w outermost orbit of an ion and centre of nucleus
99
for isoelectronic species, ionic radius, no of +ve charge
decreases
100
for isoelectronic species, ionic radius, no of -ve charge increases
ionic radius increases
101
what is Ionization energy
amount of energy required to remove the outermost electron from a isolated gaseous species
102
when Ionization enthalpy is +ve
energy is absorbed (endothermic)
103
Ionization energy is expressed in
KJ/mol
104
Ionization potential is expressed in
ev/atom
105
energy required to ionize one atom
IE/nA
106
trend of IE
IE1
107
increases in +ve charge, IE
increases
108
Zeff increases, IE
increases
109
no of orbits/radius/size increases IE
decreases
110
Se increases,IE
decreases
111
Penetration effect increases IE
increases
112
order of PE of orbitals
ns>np>nd>nf
113
proportionality of IE with stability of EC
Directly proportional
114
which orbitals have comparatively higher IE
s2,p3,p6,d5,d5,f7,f14
115
positive oxidative state increase IE
increases
116
negative oxidative state increases IE
decreases
117
IE in first period
H
118
IE in first period
H
119
ie in second period
Li
120
ie in 3rd period
Na
121
variation of ie in group 13
B>Tl>Ga>Al>In
122
if metallic character increases, ie
decreases
123
if reducing character increases, ie
decreases
124
if reducing character increases, ie
decreases
125
if basic characters increases , ie
decreases
126
in period ie
increases
127
ie in group
Decreases
128
if difference between 1st and 2nd ie is high then the element is an
alkali metal
129
if difference between 1st and 2nd ie is not that high then element is an
alkali earth metal
130
what is the most electropositive element
Cs
131
which block shows variable valency
block d ; vacant d orbitals
132
which block shows variable valency
block d ; vacant d orbitals
133
oxides of metals are
basic
134
reason for diagonal relationship
similar e/r ratio
135
why is fluorine more electronegative than nitrogen
because valence electrons in f are more closer to nucleus than that of nitrogen, zeff is more
136
most electro negative element
fluorine
137
if cation size increases
polarising power decreases
138
if positive charge on atom increases, size decreases, polarising power
increases
139
what is electron affinity
amount of energy absorbed ur released when i isolated gaseous species accepts an electron
140
if energy is absorbed
EA is positive
141
is energy is released EA
is negative
142
if EA is positive EgH is
negative
143
if EA i is negative, egh is
positive
144
more electronegative element has
more negative egh
145
1st EA is an element can be
positive or negative
146
2nd EA is an element is
always negative
147
if no of shells increases ea
decreases
148
is zeff increases electron affinity
decreases
149
if se increases, ea
decreases
150
if stability of ec increases ea
decreases
151
in period ea
increases; zeff increases
152
in group electron affinity
decreases;se increases
153
in 1st period , ea
H>He
154
2nd period ea
Ne
155
3rd period electron affinity
Ar
156
in group 17 ea
Cl>F>Br>I
157
which element has highest ea
chlorine
158
which element has lowest ea
Argon
159
in group 16 ea
S>Se>Te>Po>O
160
ea in group 15
Bi>Sb>As>P>N
161
what is electron negativity
relative tendency to attract bonded pair of atoms toward itself
162
electronegativity in group
decreases
163
EN in period
increases
164
if no of orbits increases
en decreases
165
if zeff increases, EN
increases
166
if se increases ,en
decreases
167
proportionality of en with s character
directly proportional
168
if positive oxidative state increases, en
increases
169
en in group 13
Ga>AL
170
En of hydrogen
2.1
171
EN of Li
1
172
EN of Be
1.5
173
EN of F
4
174
en of Na
0.9
175
en of S
2.5
176
en of cl
3
177
if metallic character increases en
decreases
178
if non metallic character increases en
increases
179
if Xa -Xb > 2.1 then bond is
ionic
180
if Xa-Xb<2.1/1.9 then bond is
covalent
181
neutral oxides examples
CO,NO,N2O
182
metallic/basic oxide
Na2O,MgO
183
non metallic/acidic oxide
SO2,CO2
184
amphoteric oxides
ZnO,Al2O3,Ga2O3, Sb2O3,BeO,PbO,SnO,Cr2O3,As2O3
185
bond dissociation energy of halogens
Cl2>F2>Br2>I2
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