Q.1 The order of screening effect of electrons of s, p, d and f orbitals of a given shell of an atom on its outer shell electron is: Option 1 s> p > d > f Option 2 f> d > p > s Option 3 p> d > s > f Option 4 f> p > s > d Correct Answer 1 Explanation s has greatest effect to reduce the force of attraction between the outermost electron and nucleus due to its effective charge density followed by p> d > f . Passage Text Nuclear charge actually experienced by an electron is termed as effective nuclear charge. The effective nuclear charge Z* actually depends on type of shell and orbital in which electron is actually present. The relative extent to which the various orbitals penetrate the electron clouds of other orbitals is. s> p > d > f (for the same value of n) The phenomenon in which penultimate shell electrons act as screen or shield in between nucleus and valence shell electrons and thereby reducing nuclear charge is known as shielding effect. The penultimate shell electrons repel the valence shell electron to keep them loosely held with nucleus. It is thus evident the more is the shielding effect, lesser is the effective nuclear charge and lesser is the ionization energy. Q.2 Which of the following valence electron experience maximum effective nuclear charge? Option 1 4s 1 Option 2 4p 1 Option 3 3d 1 Option 4 2p 3 Correct Answer 4 Explanation Effective nuclear charge depends on type of shell and orbital. 2p 3 is the closest to the nucleus Q.3 Which of the following is not concerned to effective nuclear charge? Option 1 Higher ionization potential of carbon than boron Option 2 Higher ionization potential of magnesium than aluminium Option 3 Higher values of successive ionization energy Option 4 Higher electronegativity of higher oxidation state Correct Answer 2 Explanation Conceptual Q.4 Ionization energy is not influenced by : Option 1 Size of atom Option 2 Effective nuclear charge Option 3 Electrons present in inner shell Option 4 Change in entropy Correct Answer 4 Explanation Conceptual Q.5 The electronic configuration of gadolinium (Atomic number 64) is Option 1 [Xe] 4f 3 5d 5 6s 2 Option 2 [Xe] 4f 7 5d 2 6s 1 Option 3 [Xe] 4f 7 5d 1 6s 2 Option 4 [Xe] 4f 8 5d 6 6s 2 Correct Answer 3 Explanation Because half field subshell more stable than partial field subshell [Xe] 4f 7 5d 1 6s 2, [Xe] 4f 8 5d 0 6s 2 is wrong Q.6 The statement that is not correct for periodic classification of elements is : Option 1 The properties of elements are periodic function of their atomic numbers. Option 2 Non metallic elements are less in number then metallic elements. Option 3 For transition elements, the 3d -orbitals are filled with electrons after 3p -orbitals and before 4s-orbitals. Option 4 The first ionisation enthalpies of elements generally increase with increase in atomic number as we go along a period. Correct Answer 3 Explanation 3p then 4s then 3d Q.7 The period number in the long fo rm of the periodic table is equal to Option 1 Magnetic quantum number of any element of the period. Option 2 Atomic number of any element of the period. Option 3 Maximum Principal quantum number of any element of the period. Option 4 Maximum Azimuthal quantum number of any element of the period. Correct Answer 3 Explanation Maximum principle quantum numbers of any element of the period is period number of long term of periodic table & 1s 2 2s 2 2p 5 period number is 2 Q.8 Assertion : The 5 th period of periodic table contains 18 elements not 32. Reason : n = 5, l = 0, 1, 2, 3, 4. The order in which the energy of available orbitals 4d, 5s and 5p increases is 5s< 4d < 5p and the total number of orbitals available are 9 and thus 18 electrons can be accomodated. Option 1 If both assertion and reason are correct and reason is the correct explanation of assertion. Option 2 If both assertion and reason are true but reason is not the correct explanation of assertion. Option 3 If asser tion is true but reason is false. Option 4 If reason is true but assertion is false. Correct Answer 1 Explanation If both assertion and reason are correct and reason is the correct explanation of assertion. Q.9 The elements in which electrons are progressively filled in 4 f-orbital are called Option 1 Actinoids Option 2 Transition elements Option 3 Lanthanoids Option 4 Halogens Correct Answer 3 Explanation 4f series elements is called Lanthanoids elements Q.10 La (lanthanum) having atomic number 57 is a member of : Option 1 s-block elements Option 2 p-block elements Option 3 d-block elements Option 4 f-block elements Correct Answer 3 Explanation d-block elements Q.11 If t he aufbau principle had not been followed, Ca (Z = 20) would have been placed in the : Option 1 s-block Option 2 p-block Option 3 d-block Option 4 f-block Correct Answer 3 Explanation d-block Q.12 Assertion : The 4f -and 5f -inner transition series of elements are placed separately at the bottom of the periodic table. Reason : (i) This prevents the undue expansion of the periodic table i.e., maintains its structure. (ii) This preserve the principles of classification by keeping elements with similar properties in a single column. Option 1 If both assertion and reason are correct and reason is the correct explanation of assertion. Option 2 If both assertion and reason are true but rea son is not the correct explanation of assertion. Option 3 If assertion is true but reason is false. Option 4 If reason is true but assertion is false. Correct Answer 1 Explanation If both assertion and reason are correct and reason is the correct explanation of assertion. Q.13 Which of the following sets contain only isoelectronic ions? Option 1 Zn 2+ , Ca 2+ , Ga 3+ , A l3+ ☐ Option 2 K+, Ca 2+ , Sc 3+ , C l- ☒ Option 3 P3-, S 2-, C l-, K + ☒ Option 4 Ti 4+ , Ar , Cr 3+ , V 5+ ☐ Explanation (a) Zn 2+ (28) Ga 3+ (28) Ca 2+ (18) Al 3+ (10) (b) K+(18) Sc 3+ (18) Ca 2+ (18) Cl -(18) (c) P3-(18) S 2-(18) Cl -(18) K +(18) (d) Ti 4+ (18) Ar(18) Cr 3+ (21) V 5+ (18) Q.14 In which of the following sets of elements, they have nearly the same atomic size Option 1 Li, Be, B, C Option 2 Mg, Ca, Sr, Ba Option 3 O, S, Se, Te Option 4 Fe, Co, Ni, Cu Correct Answer 4 Explanation d-block elements from Fe to Cu nearly same atomic size Q.15 The correct order of the sizes of C, N, P, S, is Option 1 N< C < P < S Option 2 C< N < S < P Option 3 C< N < P < S Option 4 N< C < SP < Correct Answer 4 Explanation N< C < SP < Q.16 Consider the isoelectronic species, Na +, Mg 2+ ,F - and O2-. The correct order of increasing length of their radii is ........... Option 1 F-< O 2- < Mg 2+ < Na + Option 2 Mg2+< Na + < FO < 2- Option 3 O2-< F < Na + < Mg 2+ Option 4 O2-< F - < Mg 2+ < Na + Correct Answer 2 Explanation Mg2+< Na + < FO < 2- Q.17 In which of the following pair, both the species are isoelectronic but the first one is large in size than the second ? Option 1 S2-, O 2- Option 2 Cl -, S 2- Option 3 F-, Na + Option 4 N3-, P 3- Correct Answer 3 Explanation F-, Na + Q.18 The correct order of ionic size of N 3-, Na +, F -, Mg 2+ and O 2- is : Option 1 Mg2+> Na + >> F - O 2- < N 3- Option 2 N3->> F - O 2- > Na + > Mg 2+ Option 3 Mg2+< Na + << F - O 2- < N 3- Option 4 N3-> O 2- >> F - Na + > Mg 2+ Correct Answer 3 Explanation Mg2+< Na + << F - O 2- < N 3- Q.19 From the ground state electronic configuration of the elements given below, pick up the one with highest value of second ionization energy Option 1 1 s 2 2 s 2 2 p 6 3 s 2 Option 2 1 s 2 2 s 2 2 p 6 3 s 1 Option 3 1 s 2 2 s 2 2 p 6 Option 4 1 s 2 2 s 2 2 p 5 Correct Answer 2 Explanation After 1 st IE (((1s2 2s 2 2p 6 ))) →→→ Non configuration Q.20 In which of the following pairs, the ionization energy of the first species is less than that of the second Option 1 N, P Option 2 Be +, Be Option 3 N, N - Option 4 S, P Correct Answer 4 Explanation P has half filled stability. ∴∴∴ IE is higher for P than S. -1 Q.21 IE 1 and IE 2 of Mg are 178 and 348 kcal mol respectively. The ene rgy required for the reaction Mg((()( g)))(→→→ Mg2+((() g))) +2e - is Option 1 + 170 kcal Option 2 + 526 kcal Option 3 - 170 kcal Option 4 - 525 kcal Correct Answer 2 Explanation + 526 kcal Q.22 For a given value of n (principal quantum number), ionization energy is highest for Option 1 d-Electrons Option 2 f-Electrons Option 3 p-Electrons Option 4 s-Electrons Correct Answer 4 Explanation Due to highest electron affinity. Q.23 Which one of the following is true about metallic character when the move from left to right in a period and top to bottom in a group Option 1 Increases both in the period and group Option 2 Decreases both in the period and group Option 3 Decreases in the period and increases in a group Option 4 Increases in the period and decreases in a group Correct Answer 3 Explanation Conceptual Q.24 The electronic configurations of the elements X, Y, Z and J are given below.