1) The first ionisation energy is smallest for the atom with the electronic configuration
2) In a period, the alkali metals have the
a) Highest ionisation energy
b) Largest atomic radii
c) Highest density
d) Highest electronegativity
3) The lowest ionisation potential in a period is shown by
a) Alkali metals
c) Transition elements
d) Alkaline earth metals
4) An atom with high electronegativity generally has a
a) Tendency to form positive ions
b) High ionisation potential
c) Large atomic size
d) Low electron affinity
5) Which of the following elements has the highest atomic volume ?
6) The elements of IA group give colours to the Bunsen burner flame due to their
a) Low I.P.
b) Low M.P
d) One electron in outermost shell
7) The telluric helix was given by
c) Lothar Meyer
d) De Chancourtois
8) In the periodic table on moving from left to right across a period, the metallic character of an element
c) Increases and then decreases
d) Remains constant
9) Elements of the same vertical group of the periodic table have the
a) Same atomic size
b) Same electronic configuration
c) Same number of electrons in the outermost shell of their atoms
d) Same number of atoms
10) Which of the following has the largest ionic radius ?
11) The number of elements present in period V of the periodic table is
12) The first ionisation energy of lithium is
a) Greater than Be
b) Less than Be
c) Equal to sodium
d) Equal to fluorine
13) The 3d transition series contains elements having atomic numbers from
a) 22 to 30
b) 21 to 30
c) 21 to 31
d) 21 to 29
14) The tenth element in the periodic table resembles
a) The second
b) The fourth
c) The fifth
d) The eighth
15) Which of the following elements have a strong tendency to form anions ?
a) P, S, Cl
b) As, Sb, Bi
c) Fe, Co, Ni
d) Li, Be, B
16) The attempt to classify elements by plotting the atomic weight of elements against their volumes was made by
a) Lothar Meyer
17) Transition metals fit in the periodic table between
a) III and IV group
b) I and III group
c) II and III group
d) I and II group
18) The VIII group of periodic table contains
a) 6 elements
b) 12 elements
c) 3 elements
d) 9 elements
19) In the periodic table, with the increase in atomic number, the metallic character of an element
a) Decreases in a period and increases in a group
b) Increases in a period and decreases in a group
c) Increases both in a period and a group
d) Decreases in a period and a group
20) A diagonal relationship is shown by
a) All elements with their diagonally opposite elements
b) All elements of the 3rd and 4th periods
c) Some of the elements of the 2nd and 3rd periods
d) Elements of the d – block
21) The most electropositive element of the first period is
22) In the III Period, the most acidic oxide is formed by
23) Which has the least ionisation potential ?
24) An element M forms ,containing 20% of the metal. The atomic weight of the metal is
25) Which of the following is isoelectronic with the carbon atom ?
26) The number of elements present in the fifth period of the periodic table is
27) Mercury is the only metal which is liquid at 0°C. This is due to
a) A very high ionisation energy and weak metallic bonds
b) A low ionisation potential
c) A high atomic weight
d) A high vapour pressure
28) The most acidic among the following is
29) The element with atomic number 55 belongs to which block of the periodic table
30) In the third group of the periodic table, the maximum I.E. will be of
31) The least electronegative element in the periodic table is
32) Among the pair of elements indicated, which will have similar properties?
b) 11, 20
c) 12, 10
d) 21, 33
33) The element with electronic configuration 3d44s1 is a
c) Transition element
34) The change in Zn ® Zn2+ is accompanied by a decrease in the
a) Number of valence electrons
b) Atomic mass
c) Atomic number
d) Number of shells
35) Which period and group in the long form of the periodic table contains the maximum number of elements?
a) 5th period, II group
b) 6th period, III B group
c) 6th period, II group
d) 1st period, II group
36) In which block does the element with the following electron arrangement exist
37) The electronic configuration of an element is Is22s22p63s23p63dlÂ°4s24p3 . Its properties would be similar to which of the following elements ?
38) What are the most common elements present in the earth’s crust ?
a) Oxygen, Iron, Potassium
b) Silicon, Iron, Magnesium
c) Oxygen, Iron, Silicon
d) Silicon, Aluminium, Oxygen
39) Which of the following statements correctly represents the property of elements related to the increase in atomic number in the carbon family (group IV B) ?
a) Their metallic character decreases
b) The stability of the +2 oxidation state increases
c) Their ionisation energy increases
d) Their atomic size decreases
40) In which group do all the elements not belong to the same block, and all the elements do not have the same number of valence electrons ?
a) Zero group
b) First group
c) Third group
d) Seventh group
41) In which period and which group are all the elements gases ?
a) First period, zero group
b) Third period, zero group
c) Second period, zero group
d) 1st period, second group
42) The element whose electronic configuration is 1s22s22p63s2 is a
c) Inert gas
43) A newly discovered element X is placed in group IA of the periodic table because it forms
a) An oxide which is acidic
b) A volatile chloride having the formula XCl
c) An ionic chloride having the formula XCl
44) The element with the electronic configuration 1s22s22p63s23p63d104s24p64d105s25p3 belongs to the following group of the periodic table
45) In the isoelectronic species, the ionic radii of N3-, O2- and F– are respectively given by
a) 1.36, 1.40, 1.71
b) 1.36, 1.71, 1.40
c) 1.71, 1.40, 1.36
d) 1.71, 1.36, 1.40
46) Which of the following pairs of elements behave as metalloids ?
a) Br and I
b) Pt and I
c) B and Cs
d) Al and Zn
47) The element in the III group and III period in periodic table is
48) The cation which is least stable is
49) Elements of the same group in the periodic table are characterised by the same
a) lonisation potential
c) Electron affinity
d) number of valency electrons
50) Most of the known elements are
c) Transition metals
d) Inner transition metals
51) Which of the following pairs of elements contain the same number of electrons in the outermost orbit ?
a) N, O
b) Na, Cl
c) As, Bi
d) Pb, Sb
52) Which of the following statement is not true about the long form of periodic table ?
a) It reflects the sequence of filling of electrons in order of sub-energy levels s, p, d and f
b) It helps to predict the stable valency states of the elements.
c) It reflects trends in physical and chemical properties of the elements.
d) It helps to predict the relative ionicity of the bond between any two elements.
53) Which of the following has the smallest radius ?
54) The biggest ion is
55) Which of the following pairs of elements belongs to the same period ?
a) Li, Na, K
b) Ca, Cr, Zn
c) Cr, In, Pb
d) H, He, F
56) Among the following group of elements, the one whose elements can have positive as well as negative oxidation states are
a) H, F, O
b) Na, Mg, Al
c) He, Li, Be
d) H, Cl, Br
57) Which of the following periodic table groups consists entirely of metals ?
b) IV A
c) VI A
58) Which has the highest boiling point.
59) The second ionisation potential of K, Ca and Ba (Z : K = 19, Ca = 20,Ba = 56) in decreasing order are
a) K > Ca > Ba
b) Ca > Ba > K
c) Ba > K > Ca
d) K > Ba > Ca
60) Name the block in which metals, metalloids,non-metals and inert gases are all present.
a) s -block
b) p -block
c) d – block
d) f – block
61) Among the following elements, the one having the highest ionisation energy is
62) Which of the following is formed easily ?
63) Which of the following groups may contain a metalloid ?
a) I A
b) II A
c) VI A
64) Which of the following has the least density ?
65) The combination of atoms takes place so that
a) they can gain two electrons in the outermost orbit
b) they can get eight electrons in the outermost orbit
c) they acquire stability by lowering of energy
d) they can get eighteen electrons in the outermost shell.
66) If in forming a compound AB, an electron is transferred from A to B then
a) A is divalent
b) B is oxidised
c) A and B are covalently bonded
d) The compound AB is electrovalent
67) An ionic compound A+B– is most likely to be formed when
a) the ionisation energy of A is high and the electron affinity of B is low
b) the ionisation energy of A is low and the electron affinity of B is high
c) Both the ionization energy of A and the electron affinity of B are high
d) Both the ionization of energy of A and the electron affinity of B are low
68) When an element of very low ionization potential reacts with an element with very high electron affinity, the bond formed will be predominantly
69) Which of the following statements concerning the element with the atomic number 10 is true?
a) It forms a covalent network of solids
b) Its molecules are monoatomic
c) It has a very high electron affinity
d) It has an extremely low value of ionization energy.
70) Which of the following is an ionic compound?
71) Which factor is most responsible for the increase in boiling points of noble gases from He to Xe?
a) the decrease in I.E
b) Monoatomic nature
c) Decrease in polarisability
d) Increase in polarisability
72) Which of the following is a solid with the highest melting point?
73) A metallic bond is
a) similar to an ionic bond
b) similar to a covalent bond
c) similar to neither ionic nor covalent bonds
d) formed by the movement of positively charged spheres in a sea of electrons
74) The following is in the incorrect order of decreasing boiling points:
a) HF >HI > HBr > HCl
75) Alkali metals ( Na, K etc) conduct electricity because
a) They are soft
b) They have only one valence electron
c) they react with water to give H2 gas
d) Their electrons are mobile
76) The first four ionization energy values of an element are 191,578, 872 and 5962 kcal. The number of valence electrons in the element is
77) Which of the following molecules is theoretically not possible?
78) Which of the following is an example of a super-octet molecule?
d) All the three
79) Which of the following statements is incorrect for ?
a) All the P-Cl bond lengths are equal
b) it involves sp3 hybridization
c) It has an irregular geometry
d) Its shape is trigonal bipyramidal
80) In one of the following molecules, the state of hybridisation of the central atom is not the same as in the others. Which one is it?
81) If a metal ion M3 + loses 3 electrons, its oxidation number will be
b) + 6
c) + 3
d) Â– 3
82) Write the oxidation state of phosphorus in H3PO3.
83) In the chemical reaction Cl2 + H2S 2HCl + S, the oxidation number of sulphur changes from
a) 0 to 2
b) 2 to 0
c) -2 to 0
d) -2 to 1
84) The number of neutrons in a parent nucleus X, which gives 7N14 after two successive emissions would be
85) What is X in the following nuclear reaction?
7N14 + 1H1 8O15 + X.
86) The half-life period of a radioactive element is 140 days. In 560 days a sample of this element would be reduced to …. of its initial mass.
87) In terms of energy 1 amu is equal to
a) 100 J
c) 931.1 kcal
88) The half-life period of U is 4.5 x 10 9 years. After how many years will the amount of U be reduced to half its present amount?
89) If 90Th228 disintegrates to 83Bi212, then the number of Â— and Â—particles emitted are respectively
90) The activity of a radioactive nuclide (100X) is 6.203 curie. If its disintegration constant is 3.7x 104 sec-1, the mass of X is
91) Sulphur -35 (34.96903 amu) emits a beta particle but no gamma ray. The product is chlorine-35 (34.96885 amu). The maximum energy emitted by the beta particle is
a) 16.758 MeV
b) 16.6758 MeV
c) 0.16758 MeV
d) 0.016758 MeV
92) On bombarding 7N14 with particles, the nucleus of the product formed after the release of a proton will be
93) The decay constant of a radioactive sample
a) Decreases as the age of atom increases
b) Increases as the age of atom increases
c) is independent of the age
d) Depends on the nature of activity
94) The reaction 5B8 4Be8 + 1e0 takes place due to
c) Positron decay
d) Electron capture
95) The half-life of 4 isotopes are: (I) 6.7 years (II) 8xl03 years (III) 5760 years (IV) 2.35 x l05 years. The most stable isotope is
96) The half-life period of a radioactive substance is 8 years. After 16 years, the mass of the substance will reduce from 16.0 g at the start to
a) 8 g
b) 6 g
c) 4 g
d) 2 g
97) Which element has a relatively stable nucleus?
98) Atoms of different elements having identical masses are known as
99) Which isotope is likely to be most stable?
100) 6027Co is radioactive because
a) Its atomic number is high
b) It has a high N/P ratio
c) It has a low N/P ratio
Ans 1) a
Ans Desc 1) The first IE is smallest for the element having configuration ns2np3 because IE increases in a period from left to right and decreases in a group.
Ans 2) b
Ans Desc 2)
Ans 3) a
Ans Desc 3) IE increases in a period from left to right.
Ans 4) b
Ans Desc 4)
Ans 5) c
Ans Desc 5) Alkali metals have the highest atomic sizes in their corresponding periods. Atomic size increases from Li to Fr, because as we move from Li to Fr an extra shell of electrons is added to each element. The addition of extra electrons also increases the atomic volume (atomic weight/density) from Li to Fr.
Ans 6) a
Ans Desc 6) Because of their low IP, only a small amount of energy is required to cause excitation of the outermost electron of the alkali metal and raise it to a higher energy level.
Ans 7) d
Ans Desc 7) Elements are arranged in the form of a helix with increase in atomic mass.
Ans 8) b
Ans Desc 8) Metallic character decreases along a period, because electronegativity increases along a period from left to right.
Ans 9) c
Ans Desc 9) Because group number or (group no – 10) represents the number of electrons in the outer most shell.
Ans 10) d
Ans Desc 10) Be2+< Mg2+< Ca2+< Sr2+< Ba2+
Ans 11) b
Ans Desc 11)
Ans 12) b
Ans Desc 12) The first ionisation energy of Be is greater than that of Li, because of extra stability gained by fully filled s-orbitals in beryllium (Is22s2).
Ans 13) b
Ans Desc 13) 3d-series contains 10 elements, Sc (Z=21) to Zn (Z=30).
Ans 14) a
Ans Desc 14) For example He (Z=2) and Ne (Z=10).
Ans 15) a
Ans Desc 15) P, S and Cl are non-metals. They have strong tendency to gain electrons and form anions.
Ans 16) a
Ans Desc 16)
Ans 17) c
Ans Desc 17) Transition elements lie between s- and p- blocks or II and III group.
Ans 18) d
Ans Desc 18) VIII group contains 9 elements (Fe, Co, Ni, Ru, Rh, Pd, Os, Ir and Pt).
Ans 19) a
Ans Desc 19)
Ans 20) c
Ans Desc 20) Some of the elements of 2nd and 3rd period show diagonal relationship. For example, Li and Mg, Be and Al, B and Si, C and P show diagonal relationship because of similar polarising power of ions (Ionic charge/Ionic radius).
Ans 21) a
Ans Desc 21)
Ans 22) c
Ans Desc 22)
Ans 23) b
Ans Desc 23) Least IP is that of oxygen. Nitrogen has more IP than oxygen because of half filled p- orbitals. The order is Ne > F > N > O.
Ans 24) a
Ans Desc 24) The element forms MCl3 in which M is 20% and 3Cl = 80%. 80 g. chlorine reacts with 20 g. metal. Thus 3 x 35.5 g. chlorine will react with 20 x 3 x 35.5/80 = 26.6.
Ans 25) d
Ans Desc 25) N+ is isoelectronic with carbon (both have 6 electrons).
Ans 26) c
Ans Desc 26)
Ans 27) a
Ans Desc 27)
Ans 28) a
Ans Desc 28) The most acidic among these is P2O3. In a period, on going from left to right the acidic nature of oxides increases and basic nature decreases. Down the group acidic nature of oxides decreases and basic nature increases.
Ans 29) a
Ans Desc 29) The element with Z = 55 is Cs, which is present in s-block.
Ans 30) a
Ans Desc 30) In III group B has maximum IE. The IE decreases from B to Al but then increases slightly as we move to Ga, In and Tl. The decrease in IE is due to increase in size. B atom is smallest in size, so its IE is highest.
Ans 31) d
Ans Desc 31) The electronegativity of noble gases is almost zero because of stable noble gas configuration.
Ans 32) a
Ans Desc 32) Both Al (Z = 13) and Gallium (Z = 31) are present in III A group.
Ans 33) c
Ans Desc 33)
Ans 34) a
Ans Desc 34) Zn has 30 electrons and Zn2+ has 28 electrons. Zn – 2e– ® Zn2+.
Ans 35) b
Ans Desc 35) 6th period is longest and contains 32 elements.
Ans 36) b
Ans Desc 36) The element is Germanium (Z=31) and it is present in p- block (1VA) group.
Ans 37) c
Ans Desc 37) The element is As (Z=33). It is present with nitrogen in the VA group.
Ans 38) d
Ans Desc 38) Oxygen, silicon, and aluminium are first, second and third most abundant elements in the earths crust respectively.
Ans 39) b
Ans Desc 39) The IV A group elements exhibit oxidation states of +4 and +2. In the +4 state, the compounds are covalent, while in the +2 state the compounds are ionic. The +4 state becomes less important in Ge, Sn and Pb, because they prefer to exhibit the +2 state for ionic bond formation due to the inert pair effect. The inert pair effect decreases down the group from Ge to Pb and the stability of the +4 oxidation state decreases and that of the +2 state increases. Thus the stability of M2+ ions is in the order Ge2+< Sn2+< Pb2+.
Ans 40) a
Ans Desc 40) In zero group the number of electrons in the outermost shell of He is 2 and in others it is 8.
Ans 41) a
Ans Desc 41) In the first period hydrogen and helium are gases and in the zero group He, Ne, Ar, Kr, Xe and Rn are all gases.
Ans 42) a
Ans Desc 42) The element with configuration Is22s22p63s2 is an alkaline earth metal (Mg).
Ans 43) c
Ans Desc 43) Because it forms an ionic chloride having formula XCl (e.g. NaCl).
Ans 44) b
Ans Desc 44) The element is antimony (Z=51). It is present in VA group.
Ans 45) c
Ans Desc 45) The ionic radii decreases in the order
Ans 46) d
Ans Desc 46) Al and Zn can react with acids as well as bases. These are amphoteric.
Ans 47) d
Ans Desc 47)
Ans 48) c
Ans Desc 48) tends to change to stable ion.
Ans 49) d
Ans Desc 49)
Ans 50) a
Ans Desc 50) The maximum number of elements in the periodic table are metals.
Ans 51) c
Ans Desc 51) As and Bi are present in the VA group.
Ans 52) b
Ans Desc 52)
Ans 53) d
Ans Desc 53) The order is
Ans 54) b
Ans Desc 54)
Ans 55) b
Ans Desc 55) Ca, Cr and Zn are present in IV thperiod.
Ans 56) d
Ans Desc 56)
Ans 57) a
Ans Desc 57) II A group contains alkaline earth metals.
Ans 58) d
Ans Desc 58) All are non polar molecules but Xe has the highest van der Waals forces because it has the maximum number of 8 electrons in the outermost shell.
Ans 59) a
Ans Desc 59)
Ans 60) b
Ans Desc 60) p-block contains metals, metalloids, non- metals and inert gases.
Ans 61) b
Ans Desc 61) The element with Ans. [Ne]3s23p3 has the highest ionisation energy because IE increases in a period from left to right. Moreover, this element is P, which has half filled p-electrons.
Ans 62) a
Ans Desc 62) Ca2+ is easily formed by the loss of two electrons. Ca – 2e–Â® Ca2+.
Ans 63) c
Ans Desc 63) IA and IIA groups contain all metals. VIA group contains metalloids such as Se and Te.
Ans 64) b
Ans Desc 64) Lithium is the lightest metal having a density of 0.53 g/mL.
Ans 65) c
Ans Desc 65)
Ans 66) d
Ans Desc 66) Electrovalent bonds are formed by transference of electrons from one atom to the other.
Ans 67) b
Ans Desc 67)
Ans 68) a
Ans Desc 68) Ionic bonds are formed between atoms of low I.E. and high E.A.
Ans 69) b
Ans Desc 69) Atoms with atomic number 10 do not combine with each other since it is an inert gas. As such its molecules are monoatomic.
Ans 70) c
Ans Desc 70) KI is an ionic compound while are covalent compounds.
Ans 71) d
Ans Desc 71) As the size of the noble gas increases, the polarisability increases accordingly. With increase in polarisability, the magnitude of van der Waals force of attraction and hence the boiling points increases from He to Xe.
Ans 72) c
Ans Desc 72) SiO2 is a covalent network solid. In ice, H2O molecules are held by weak H-bonding, CO2 had dipole-dipole interactions while He has van der Waal’s forces of attraction. Since the breaking of covalent bonds requires much energy, therefore SiO2 has the highest melting point.
Ans 73) d
Ans Desc 73)
Ans 74) d
Ans Desc 74) The boiling point decreases as the size or the molecular mass of the molecule decreases, ie; GeH4 > SiH4 > CH4. Therefore, order (d) is wrong. All the remaining orders are however, correct.
Ans 75) d
Ans Desc 75)
Ans 76) c
Ans Desc 76) Since there is a large jump between the third and fourth ionization energies, therefore after removal of the third electron, the cation has the inert gas configuration, therefore, the valency of the metal is 3.
Ans 77) c
Ans Desc 77) Due to the absence of d- orbitals, O cannot expand its valency beyond 2, therefore OF4 is theoretically not possible.
Ans 78) c
Ans Desc 78) All the molecules are super octet molecules since in all these molecules, the central atom has more than 8 electrons.
Ans 79) a
Ans Desc 79) In PCl5, the two axial bonds are longer than the three equatorial bonds.
Ans 80) a
Ans Desc 80) (a) Total valence electrons in BF3 =3+3Â´ 7=24.
The hybridisation of B in BF3 is sp2.
(b) Total valence electrons in
Now . Therefore hybridisation of O in H3O+ =sp3.
(c) Total valence electrons in NH3 =
Hybridisation of N in NH3=sp3.
(d) Hybridisaton of P in PCl3=sp3
Ans 81) b
Ans Desc 81) M-3e-M3+-3e-M6+ Thus oxidation number of M = + 6.
Ans 82) c
Ans Desc 82) 3(+ l) + x + 3(-2)=0 or x = 6-3= + 3
Ans 83) c
Ans Desc 83) Cl2 + H2S -22HCl + S 0 (Oxidation number changes from -2 to 0)
Ans 84) d
Ans Desc 84) 5X146Y147N14. The number of neutrons in 5X14 = 4 – 5 = 9.
Ans 85) d
Ans Desc 85) X is a gamma ray.
Ans 86) d
Ans Desc 86) = no. of half lives =. Now left over concentration = = 1/24=1/16.
Ans 87) b
Ans Desc 87) One amu = 931.5 MeV.
Ans 88) c
Ans Desc 88) Because 4.5 x 109 years is the half life period of
Ans 89) b
Ans Desc 89) Suppose the number of alpha and beta particles emitted are a and b respectively. Now 4a = 228-212 = 16 or a = 4. Similarly 2a-b =90 – 83 = 7. Now b = 2a-7 = 2×4-7 =1. Thus the number of alpha and beta particles emitted are 4 and 1 respectively
Ans 90) b
Ans Desc 90) One curie = 3.7 x 1010 disintegrations sec-1. Now N0 = A, where A, is disintegration constant and N0 is the amount of X left after time t. A is the activity in curie. Thus 3.7 x104x N0 = 6.023 x3.7×1010
Or No = = 6.023 xl06. Now 6.023 x 1023 atoms are present in 100 g. (At. wt of X = 100 g.)
Therefore, 6.023 x 106 atoms are present in, = 100 x 10-17g = 10-15g.
Ans 91) c
Ans Desc 91) The mass converted into energy is =34.96903 amu-34.96885 amu = 0.00018 or 1.8x 10-4 amu. But 1 amu = 931.5 MeV. Thus mass converted into energy = 1.8 x10-4 x 931.5 = 0.1676 MeV.
Ans 92) b
Ans Desc 92) 7N14 + 2He48O17 + 1H1
Ans 93) c
Ans Desc 93) The decay constant depends only on the nature of the radioactive sample.
Ans 94) c
Ans Desc 94) A positron is emitted.
Ans 95) d
Ans Desc 95) The greater the half-life period, the smaller is the decay constant and the more stable is the isotope.
Ans 96) c
Ans Desc 96) No. of half lives, n = 16/8 = 2. Amount left = 16/2n = 16/4 = 4 g.
Ans 97) c
Ans Desc 97) Fe has maximum binding energy per nucleon.
Ans 98) c
Ans Desc 98) Isobars have different atomic numbers but the same mass numbers.
Ans 99) c
Ans Desc 99) Because the N/P ratio is smallest in this case
Ans 100) b
Ans Desc 100) A high N/P is responsible for neutron decay.