Atomic Structure Questions and Answers

56 A volume V of air saturated with water vapour exert a pressure P Pressure of saturated vapour is Po If the volume is made V 2 isothermally the final pressure will be a P c 2P Po VI b 2Po d 2 P Po

In how many elements the last electron will have the following set of quantum numbers n 3 and 1 1 a 2 b 8 c 6 d 10

to the same princip levels have different eccentricity More is the eccentricity of a subshell more is the opportunity of the electrons residing in that subshell to be closer to the nucleus Thus the subshell will posses more penetration power and the corresponding electrons belonging to the subshell will have more power to shield the nuclear charge

th When an electron of hydrogen atom jumps from n orbit to n th orbit let the frequency of emitted radiation be v According to Bohr s theory hv En E y or or or or 1 y 2 m 4 n h 27 me h n n 2 m 4 2 25 1 2 1 2 h3 n n 2 m 1 h 1 n n 2 m 4 1 1 ch3 n n V R 27 me 1 1 ch3 n n 1 1 n n 2 m 4 n h for H Z 1 9 1 wavelength of emitted radi ation and c velocity of light 10 R is a constant known as Rydberg s constant 27 me4 wave number 11

Pressure is determined as force per unit area of the surface The SI unit of pressure pascal is 1 Pa 1 Nm 2 If mass of air at sea level is 1034 g cm2 calculate the pressure in pascal

3 Determine the wavelength and frequency of the radiation having the longest wavelength in Lyman series of hydrogen atom R 109678 cm Ans Rydberg s equation R 11 In case of Lyman Ln n series n 1 n 2 or any other higher integral values 3 4 5 etc For the wavelength to be the longest the difference in energies between the two energy levels should be minimum Hence n 2

When the electron moves in an elliptical orbit the nucleus remains at one of the foci

Considering the following ionisation steps A g A g e AH 100 eV A g A g e AH 250 eV Select the correct statements A IE of A g is 100 eV B IE of A g is 150 eV C IE of A g is 150 eV D IE of A g is 250 eV

One litre of oxygen containing 1 argon is passed over heated copper and heated magnesium till no further reduction in volume took place the volume finally contained by gas would be approximately 2 200 ml 4 1 litre ov 1 Zero 3 10 ml duco f

tal energy of an electron revolving energy of an electron revolving in n th orbit En Kinetic energy Potential energy mv 1 r Ze r 1 Ze Ze 1 m mx Ze Ze Ze2 mr r Ze 1 X Total 0 24 Ze 7 mr

KAMA Calculate the shortest and longest wavelengths i Lyman series of hydrogen spectrum

A 2 0 B 0 2 65 The four quantum numbers of the outermost orbital of K atomic no 19 are 1 A n 2 1 0 m 0 s 2 alajoging no 1 C n 3 1 1 m 1 s 2 1 B n 4 1 0 m 0 s 2 0 31 1 D n 4 1 2 m 1 s vodunu 2 12511

A 20 litre container at 400 K contains CO g at pressure 0 4 atm and an excess of SrO neglect the volume of solid SrO The volume of the container is now decreased by moving the movable piston fitted in the container The maximum volume of the container when pressure CO attains its maximum value will be Given that SrCO s SrO s CO g K 1 6 atm

During the working of a galvanic cell and with the passage of time 1 Spontaneity of the cell reaction decreases E decreases 2 Reaction quotient Q decreases Ell increases cell 3 Reaction quotient Q increases El decreases 4 At equilibrium Q KE cell 0 eq cell

Wave number of a spectral line in the Lyman seri of H atom is 82260 cm 1 Show that this line ha appeared in this series due to the return of th electron from the second to the first orbit

If same energy is supplied to electron in ground state of Hydroger as well as He electron jump to 5th main shell in Hydrogen then final orbit of electron in Het is A 2nd B C 3rd D 4th

29 Iron in nature exists in three isotopic forms Fe54 Fe56 Fe57 The percentage abundance of Fe54 and Fe57 are equal and the average atomic mass of Fe is 55 95 then percentage abundance of Fe56 is 1 80 2 85

The I P of an atom is 16eV What are wrong values of the value of first excitation potential A 10 2 eV B 12 eV C 14 eV D 16 eV

6 3 7R 144 cm 1 1 x eV 4 3 2x eV 9R 400 In a hydrogen atom if the energy of electron in the ground state is x eV then that in the 2nd excited state of Het is cm 1 4 2 x ev 9 9 4 x eV 4

In the complex Ni H O NH3 4 2 the magnetic moment u of Ni is 1 Zero 3 1 73 BM 2 2 83 BM 4 3 87 BM

Q58 For an orbital in B4 radial function is R r 1 Z 9 6 ao 3 14 where o 4 0 e 0 2 Zr and a 0 529 Z atomic number r radial distance from nucl ao The radial node of orbital is at distance from nucleus A 0 529 B 2 12 C 1 06 D 0 423

Consider the following statements Mod A S Cr NH 1 is a inner orbital complex with crystal field stabilization energy equal to 1 2 A S The complex formed by joining the CN ligands to Fe ion has theoretical value of spin only magnetic moment equal to 1 73 B M roads to visin 100 S Na S Na Fe CN NO Na 4 Fe CN NOS In reactant and product the oxidation states of iron are same and arrage in the order of true false 1 FTF 2 TTF 3 TT T 4 FFF

In an atom has 2K 8 L 18 M and 2N in the ground state the total number of electron having magnetic quantum number m 0 is 2 10 1 6 3 7 4 14

The P E of an e in a perticular shell of H atom is 3 02 eV then calculate the radius of that perticular shell 1 4 761 3 2 116 2 8 464 4 0 529

Which of the following represent the first excited state of sulphur 1 1 111 2 1 111 3 1 111 4 1 1 1 1 11

3 Main axis of a diatomic molecule is z orbital p and p overlap with each other to form which of th following molecular orbitals 1 molecular orbital 2 o molecular orbital 3 8 molecular orbital 4 No bond will form

Which of the following formulae expresses the law of equivalent correctly m E E a m b E E m m

The frequency of radiation emitted when the electron falls from n 4 to n 1 in a hydrogen atom will be Given ionization energy of H 2 18 x 10 18 J atom and h 6 625 x 10 34 Js a 1 54 x 10 5 S 1 c 3 08 x 10 5 S 1 b 1 03 x 10 5 S 1 d 2 00 x 10 5 S 1 2004

74 If the uncertainity in position and velocity is same then the value of Ax is 1 Ax 3 Ax h m 2 2m 2 AX 4 Ax 2 m h VAT

74 Among the triatomic molecules ions BeCl N3 N O NO2 O3 SCI ICl2 I3 and XeF the total number of linear molecules s ion s where the hybridization of the central atoms does not have contribution from the d orbital s is JEE Adv 2015 Atomic number S 16 Cl 17 I 53 and Xe 54

4 The nodal plane in the bond of ethene is located in A the molecular plane B a plane parallel to the molecular plane C a plane perpendicular to the molecular plane which bisects the carbon carbon a bond a D a plane perpendicular to the molecular plane which contains the carbon carbon bon

Which of the following sets of quantum numbers represents 2007 the highest energy of an atom a n 3 1 0 m 0 s 1 2 b n 3 1 1 m 1 s 1 2 c n 3 1 2 m 1 s 1 2 d n 4 1 0 m 0 s 1 2

5 ASF molecule is trigonal bipyramidal The orbitals of As atom involved in hybridisation are a d d S PxPy b dxy S Px Pp Pz c S Px Py Pz dz d2 2 S Px Py Pr d

6 The potential energy of the electron present in the ground state of Li2tion is represented by 38 a b TEO c 4TE OT d 3e 4TE OF 3e 4TE OF

22 How many times does the electron go round the first Bohr s orbit of hydrogen in one second

Number of peroxide linkage in CrO5 H SO5 H S O8 are respectively 1 2 1 2 2 2 2 2 3 1 1 1

Based on Laws of chemical combination which of the following statement is correct 1 In compound A 1 00g nitrogen combines with 0 57g oxygen In compound B 2 00g nitrogen combines with 2 24g oxygen In compound C 3 00g nitrogen combines with 5 11g oxygen These results obey Law of multiple proportion 2 In the reaction Hydrogen g Oxygen g water vapour the ratio of volumes is 2 1 2 This illustrates Avagadro s law 3 Two samples of lead oxide were separately reduced to metallic lead by heating in a current of hydrogen The weight of lead from one oxide was half the weight of lead obtained from the other oxide The data illustrates Law of definite proportions 4 A sample of pure carbon dioxide irrespective of its source contains 27 27 carbon and 72 73 oxygen

When 6x10 5g of a protective colloid was added to 20 mL of a standard gold sol the precipitation of latter was just prevented on addition of 2 mL of 10 NaCl solution X The gold number of a protective colloid is 100 What is the value of x

9 In hydrogen atom energy of first excited state is 3 4 eV Then find out K E of same orbit of hydrogen atom a 3 4 eV c 13 6 eV b 6 8 eV d 13 6 eV 2002

The radius of the second Bohr orbit for hydrogen atom is Planck s Constant h 6 6262x10 34 Js mass of electron 9 1091x10 31kg charge of electron e 1 60210 10 19 C permittivity of vacuum 2017 A 8 854185 10 2kg m A 2 12 B 1 65 C 4 76 D 0 529

If the energy absorbed by each X molecule of a gas is 3 5 x 10 19 J and the bond energy of X is 180 6 kJ mol 1 then the kinetic energy per atom will be 1 2 5 x 10 19 J 3 2 5 x 10 20 J 2 5 0 10 20 J 4 1 5 10 19 J Office A

20 The angular momentum of an electron in a Bohr s orbit of H atom is 42178x10 34 kg m sec wavelength ing Calculate the spectral life emitted when electron falls from this level to next lower level

1 The correct set of four quantum numbers for the valence electrons of rubidium atom Z 37 is a 5 0 0 1 2 1 c 5 1 1 2 JEE Mains 2014 1 b 5 1 0 d 5 0 1 2 1 2

2 What is the nature of the bond between B and O in C H5 2OBF3 a Covalent c Ionic bond b Coordinate covalent d Banana shaped bond

of electrons in the orbitals belonging to the same subshell does not take place until bers and Hund s rule of maximum multiplicity pairing vo electrons in an atom can have the each orbital belonging to that subshell has got one electron each i e is singly occupied This forms the basis of the electronic structure of atoms i ii EXERCISES i ii iii Calculate the number of electrons which will together weigh one gram Calculate the mass and charge of one mole of electrons Calculate the total number of electrons present in one mole of methane Find a the total number and b the total mass of neutrons in 7 mg of C Assume that mass of a neutron 1 675 x 10 27 kg Find a the total number and b the total mass of protons in 34 mg of NH at STP Will the answer change if the temperature and pressure are changed How many neutrons and protons are there in the following nuclei C 180 Mg Fe Sr 24 88 38 13 26 mber 7 and

Subjective 65 The number of water molecule s directly bonded to the metal centre in CuSO4 5H O is 66 Based on VSEPR theory the number of 90 degree F Br F angles in BrF is 5

Number of maximum possible electron s in Zn for which n l 4 is 2 uto 4 2n 1 4 3 8 2 6 4 12 2x16

P 49 2 3 An excited Li 2 ion emitted a photon corresponding to the second line of Balmer series This photon liberated an electron from the stationary atom in ground state Find the velocity of the electron emitted a 3 108 cm s 1 b 3 10 4 cm s c 3 x 10 6 cm s sonite 58 d None of these

5 Which of the following has covalent as well as ioni bond a NaCl b NaOH c H O d HC1

50 The distance of separation between third and fourth orbit of Li2 is 1 1 23 A 3 2 82 A 2 0 41 A 4 1 41 A