MCQ on Atomic Structure,Periodic Properties & Chemical bonding

Test Atomic structure, Periodic Properties chemical bondingQuestions: 1. One among the following set of quantum numbers defines the highest energy electron in scandium (I) ion (a) n = 3, =1, m = 0, s = -1/2 (b) n = 3, =0, m = 0, s = -1/2 (c) n = 4, =0, m = 0, s = +1/2 (d) n = 3, =2, m =2, s = +1/2 2. In the formation of from N2 the electron is removed from (a) a orbital (b) a orbital (c) orbital (d) orbital 3. In which of the following set of molecules is the order of boiling point incorrect? (a) Xe > Ar > He (b) HCl > HF > HBr (c) H2O > H2Se > H2S (d) C3H8 > C2H6 > CH4 4. Which of the following statement is correct (a) Polarization of an anion is maximum by high charged cation (b) Small sized cation minimizes the polarization (c) A small anion brings about a large degree of polarization (d) A small anion undergoes a high degree of polarization. 5. Which among the following molecules is diamagnetic (a) Superoxide ion (b) oxygen molecule (c) carbon molecule (d) unipositive ion of nitrogen molecule. 6. The energy of orbital is greater than orbital because (a) orbital is bigger than orbital (b) orbital is a bonding orbital whereas is an antibonding orbital (c) orbital has a greater value of n than orbital (d) orbital is formed only after orbital is formed. 7. The bond that stabilizes the secondary structure of protein is (a) Covalent (b) Ionic bond (c) Coordinate bond (d) Hydrogen bond 8. Which of the following does not contain any coordinate bond (a) (b) (c) (d) 9. The transition of an electron from a 4s orbital to 1s orbital in hydrogen atom causes (a) optoelectronic effect (b) a Lyman line (c) increases in kinetic energy of electron (d) conversion of to H atom. (e) a Balmer line 10. The chemical species having same number of electron in the outermost and penultmate shell is (a) (b) (c) (d) 11. From among the following triatomic species the least angle around the central atom is in (a) O3 (b) (c) (d) H2S 12. The ionization energy of gaseous Na atoms is 495.8 kJ . The lowest possible frequency of light that ionize a Na atom is (a) 1.24 1015s-1 (b) 4.76 1014s-1 (c) 1.24 1012s-1 (d) 3.15 1014s-1 13. According to Planck’s equation, =hv. The energy corresponding to intense yellow line of sodium at 589 nm is (a) 2.11 eV (b) 43.37 eV (c) 47.12 kJ (d) 2.11 kcal 14. The threshold wavelength for the ejection of electron from metal X is 330nm. The work function for the photoelectric emission from metal X is (h=6.6 10 -34 J.sec) (a) 1.2 10-20 J (b) 6 10-19 J (c) 1.2 10-20 J (d) 6 10-12 J 15. An atom emits energy equal to erg. In which part of the electromagnetic spectrum does part of the electromagnetic spectrum does the corresponding line lie? (a) UV region (b) Infrared region (c) Visible region (d) Microwave region. 16. The bond order in is the same as in (a) (b) (c) CO (d) 17. The Hybridisation of phosphorous in POCl3 is the same as (a) P in PCl3 (b) S in SF4 (c) Cl in ClF3 (d) B in BCl3 18. The energy of the first Bohar’s orbit is then the energy of the fifth Bohar orbit is (a) -2.1710-11 ergs (b) -8.6810-13 ergs (c) -5.4210-10 ergs (d) -2.0810-11 ergs 19. What transition in ion shall have the same wave number as the first line in Balmer series of hydroghen spectrum? (a) 32 (b) 64 (c) 53 (d) 75 20. An equilibrium mixture of Nitrogen gas and water vapours is taken in a 2 litre flask at 27oC and 1.2310-2 atm. Pressure. What is the mass of the gas at. (a) (b) (c) 1.410-2 g (d) 0.07 g 21. In which of the following molecules the central atom does not use sp3 hybrid or bitals in its bonding (a) (b) Be (c) SO2Cl2 (d) 22. The correct increasing bond angle among BF3, PF3 and ClF3 follows the order (a) BF3 > PF3 > ClF3 (b) PF3 > BF3 > ClF3 (c) ClF3 > PF3 > BF3 (d) BFPF3 > ClF3 23. The correct order of increasing electropositive character amongst Cu, Fe and Mg is (a) CuFe < Mg (b) Fe < Cu < Mg (c) Fe < Mg < Cu (d) Cu < Fe < Mg 24. The size of the Ionic species is correctly given in the order (a) (b) (c) (d) 25. If the electronegativity difference between two atom A and B is 2-0, then the percentage of covalent character in the molecule is (a) 54% (b) 46% (c) 23% (d) 72% 26. There are two nodes in the radial probability distribution curve for the orbital with (a) n = 2, =0 (b) n = 3, =1 (c) n =4, =3 (d) n =3, =0 27. The bond angle in H2S (for H -S)-H is (a) same as that of Cl – Be – Cl in BeCl2 (a) greater than H –N –H bond angle in NH3 (c) greater than H –Se –H and less than H –O –H (d) same as Cl –Sn –Cl in SnCl2. 28. If the ionic radii of and are about 1.34 Ao each, then the expected values of atomic radii of K and F should be respectively (a) 1.34 and 1.34Ao (b) 2.31 and 0.64 Ao (c) 0.64 and 2.31 Ao (d) 2.31 and 1.34 Ao 29. One among the following is the incorrect order of increasing ionization energy (a) (b) K < Ca < Sc (c) Au < Ag < Cu (d) Cs < Rb < K 30. Which of the following is false? (a) 3s orbital is spherically symmetrical with two nodes (b) dx2 –y2 orbital has lobes of electron density in XY plane X and Y axis (c) The radial probability curve of 1s, 3p and 5d have one, two and three regions of maximum probability. (d) has zero electron density in XY plane 31. The d-orbitals involved in dsp2 hybridisation is (a) (b) (c) (d) 32. A 5.82 g siliver coin is dissolved in nitric acid. When sodium chloride is added to the solution, all the silver is precipitated as AgCl. Precipitate weighs 7.20 g. What is the percentage of silver in coin? (a) 98% (b) 93.1% (c) 86% (d) 82 33. Which of the following combination of atomic orbitals is correct. (e) none of these (a) (b) (c) (d) 34. In one among the following molecu;es the state of hybridization of the central atom is not the same as the others (a) B in BF3 (b) O in H3 (c) N in NH3 (d) P in PCl3 35. The state of hybridization of sulphur in SO2 is same as that of sulphur in (a) SCl2 (b) SO3 (c) (d) SF4 36. The magnetic character of oxygen molecules is the same as that of one of the following molecules (a) Nitrogen (b) Carbon (c) Peroxide ion (d) Boron 37. The density of the nucleus is (a) 104 g/cc (b) 1014 g/cc (c) 10-4 g/cc (d) 10-14 g/cc 38. A diatomic molecule has a dipole moment of 1.2D. If its bond distance is 1.0 Ao, what fraction of an electronic charge, e exists on each atom? (a) 12% of e (b) 18% of e (c) 25% of e (d) 29% of e 39. How many electron are used in bonding the Lewis structure of (oxalate) ion? (a) 22 (b) 20 (c) 18 (d) 14 40. Energy required to stop the ejection of electrons from Cu plate is 0.24 eV. Calculate the work function when radiation of nm strikes the plate (a) 24.3 eV (b) 24 eV (c) 4.65 eV (d) 4.95 eV Keys: 1 c 2 a 3 b 4 a 5 c 6 c 7 d 8 c 9 b 10 c 11 d 12 a 13 a 14 d 15 c 16 a 17 a 18 b 19 b 20 c 21 b 22 c 23 d 24 b 25 a 26 d 27 c 28 b 29 c 30 d 31 c 32 b 33 b 34 a 35 b 36 d 37 b 38 c 39 d 40 c Answers: 1. ion has conf. = 1s22s22p63s23p63d14s1. Highest energy electron is 4s. 2. For N2 molecule the configuration is 3. B.pt of HF > HBr > HCl.HF has H bonding but for other hydrides the b.p increases from HCl to HBr to HI due to increase in the van der Waal’s forces. 5. Configuration of C2 molecule is 8. has H bond 9. The transition from higher to first orbit causes appearance of L Lyman line. 10. Configuration of ion is 11. In H2S the bond < H – S – H is close to 90o 12. E = hv or v = 13. As 1 eV = 1.602 (Note. Also 1 eV=1239 nm or 23 kcal/g-atom ) 14. Work function is given as = or work function = 15. The wavelength corresponding to energy =4.965 Visible region extends from 3800 - 7600 16. B.O of = = B.O of 17. P in POCl3 is sp3 hybridised i.e., H = P in PCl3 is also sp3 hybridised i.e., H = =4 18. Energy of first Bohar orbit = -2.171011 ergs energy of 5th orbit = 20. The number of modes of gaseous mixture, n = As the mixture is equimolar nN2 = 0.5 & nH2O = 0.5moles At -27o C water vapours change to water solid] mass of gas shall be only due to N2 gas = 28 21. In Be i.e. Be is sp2 hybridised 22. In BF3, P is sp3 hybridised, the molecule has pyramidal shape bond is less than 109o - and greater than 100o. In ClF3, Cl is sp3 d hybridized, the molecuw has a T- shape the bond angle is close to 90o. 24. All the given species are isoelectronic and their size depends on the nuclear charge i.e., greater the nuclear charge, smaller is the size. 25. The percentage ionic character is related to electronegativity difference between the two atoms. It is given by Hannay & Smith relationship. %age ionic character =16(XA – XB) + 3.5 (XA – XB)2 Here, XA and XB are electronegativity of two atoms A & B %ionic character =16(2) + 3.5(2)2 =46% 27. The bond in BeCl2 =180o, in NH3 = 107o, in H2O =104.5o, in SnCl2 =119o whereas that of is close to 90o. 28. The size of K should be greater than its positive ion and that of F should be smaller than its –ve ion . 29. The ionization energy of Au > Ag. It is because of the filling of (n-2) f-orbitals as a result of which the effective nuclear pull increases. 30. orbital has two lobes along Z-axis and a color of high electron density along xy plane. 31. 32. Fraction of Ag in AgCl = weight of Ag in 7.20 g AgCl =0.753 hence the 5.82 g coin contains 5.42 g Ag = 0 38. The fraction of an electronic charge is =0.25 e =25% of e 39. The oxalate ion is 40. Energy of photon =work function + =work function + eV0 …..(1) Where e = electronic charge V0 = Stopping potential and eV0 is equal to energy required to stop ejection of electron. E/photon = h C/ = =4.89 eV So from (1) 4.89 = Work function + 0.24 Work function = 4.65 eV Atomic structure, Periodic Properties chemical bonding 4 *** Prof Shallu Aggarwal Contact #. 2230216 Mobile #. 98152-08983 ***