Atomic Structure Questions and Answers

For particles having same kinetic energy the de broglie wavelength Directly proportional to mass Inversely proportional to speed Inversely proportional to square root of mass Inversely proportional to square root of speed

0 The energy of an electron in the first Bohr obit of H atom 50 13 6 e Chemical Arithmetic Atomic Structure is 13 6 eV Then which of the following statement s is are correct for He I The energy of electron in second Bohr orbit is 13 6 eV II The kinetic energy of electron in first orbit is 54 46 eV III The kinetic energy of electron in second orbit is 13 6 eV IV The speed of electron in the second orbit is 2 19 106 ms 1 I and II 2 I II and III 3 All are correct 4 None of these max 18 electron s are possible with nx conditio F1 1 facitu ar s 13 6 V 11 94 R H N 54 46 III fa IV 1 2 I II e III 3 4 13 6 el 2 1

c excited state of Mg 9 Ionisation potential of hydrogen atom is 13 6 eV Hydrogen atom in the ground state are excited by monochromatic light of energy 12 1 eV The spectral lines emitted by hydrogen according to Bohr s theory will be CBSE PMT 1992 M13 a one three b two d four 3 wz 2 131

4 Can t be determined 4 Hond 6 8 eV 56 If the P E of an electron is 6 8 eV in hydrogen atom then 56 ISSIGA TRHY UN SAP E what is the K E total energy and the orbit where electron 3 K E exist are respectively 1 K E 6 8 eV Total energy 6 8 eV n 2 2 K E 3 4 eV Total energy 3 4 eV n 2 3 K E 3 4 eV Total energy 3 4 eV n 4 4 None of these 1 K E 6 8 eV 2 K E 3 4 eV 3 K E 3 4 eV 4 3 6 8 eV n 2 3 3 4 eV n 2 f 3 4 eV n 4 D L

55 The maximum and minimum number of electrons in Co having 2 s 1 1 2 1 7 0 2 2 5 5 2 Can t be determined e P F of an electr in its ground state will be C 3 4 4 2 1 2 read and sear 1 1 2 55 12 s 1 7 0 2 2 5 3 5 2 4 Hand

3 K E 3 4 eV 3 3 4 eV n 4 4 None of these 4 T 57 A 2 kW radio transmitter operates at a frequency of 400 57 2 kW Hz How many photons per second does it emit 1 1 71 x 1021 2 1 88 1033 3 6 02 x 1023 4 7 55 1033 n 4 R Mhu 1 1 71 x 1021 2 1 88 x 1033 3 6 02 x 1023 4 7 55 x 1033 400 Hz for at 2x103 6 626x104 X

85 Which of the following is in order of increasing covalent 85 character 1 CCl4 BeCl BCl3 LICI 2 LICI CCI4 BeCl BCla 3 LICI BeCl BCl3 CCl4 4 LICI BeCl CCl4 BC13 j J

How many a 58 grams NaCl contain more Cl atoms than 0 4 mol Cl b The energy lost by an electron that moves from the sixth to the second orbit in a Hatom is 4 84x10 1 c When an electron moves from the third to the second orbit in the H atoms it emits a red photon d In a photo absorption process the electron loses energy e The line spectra produced by atoms cannot be used to analyze unknown substances t if an electron that is located in n 2 in Habsorbs 4 497x10 19 J will end up in the n 4 energy level O 5 statements 4 statements 3 statements 2 statements Ostatements

4 28 23 J K After hp 1 n 1 s 2 n 2 p n 1 d n 2 s R 8 35 m k 3 20 J K 4 28 23 J K orbitals are filled the next orbital filled will be 87 np h ch H DIG I SAT fau np 1 5 1 n 1 s 2 n 2 p 3 n 1 d 4 n 2 s

160 4 None of these 74 Value of screening constant for 39th electron of 39Y 1 39 2 36 3 18 4 20 4 74 Y 39 39 1 39 2 36 3 18 4 20 for fre 10 15 25 22p6 35 3 p 45 44 036 28 36 2 36

Which of the following electronic configuration represents a sudden large gap between the values of second and third ionisation energies of an element 1 1s 2s 2p 2 1s 2s 2p 3s 3p 3 1s 2s 2p6 3s 3p 4 1s 2s 2p6 3s

If the P E of an electron is 6 8 eV in hydrogen atom then what is the K E total energy and the orbit where electron exist are respectively A B C K E 6 8 eV Total energy 6 8 eV n 2 K E 3 4 eV Total energy 3 4 eV n 2 K E 3 4 eV Total energy 3 4 eV n 4

9 From elementary molecular orbital theory we can deduce the electronic configuration of the singly positive nitrogen molecular ion N as 2 A 015 015202 202s 22p 02p B 01s201520252025 202p 2p C 0 20 o 015 0 15 025 0 25 02p 2p4 D 15 0 15 025 02s 2p 2p O F C 20 2 On 2 0 2022 1

size 1 3 Decrease B CI Ipcrease Decrease B CI B CI Decrease Increase Decrease Decrease Decrease Decrease C S C S C S Decrease Increase Decrease Decrease Decrease Decrease N P Increase N P Increase N Decrease et to 83 31 1 Decrease 3 B 4 CI Increase B Decrease CI Decrease Increase Decrease CI C S Decrease Decrease Decrease C Decrease Increase Decrease S N P Decrease Decrease Increase N Increase P Decrease N Li Ng Ic Rb Decrease Be mej 4 0 40A 2rty f

31 Suppose the elements X and Y combine to form two compounds XY and X3Y When 0 1 mole of XY weights 2 10 g and 0 05 mole of X3Y weighs 9g the atomic weights of X and Y are 1 20 30 2 2 30 20 3 40 30 4 60 40

The pH of mixture obtained by mixing Vml each of 0 1M salicylic acid and 0 1M NaOH is x The Ka 1 and Ka of salicylic acid are 10 4 and 10 7 respectively at T Kelvin The value of x is 5 5 The value of x is 1 5 The pH of above mixture is independent of concentration of salt formed If V mL 0 1 M NaOH is further added to the above mixture complete neutralisation of salicylic acid takes place

b a ground state of Na e excited state of Mg d excited state of Al 9 Ionisation potential of hydrogen atom is 13 6 eV Hydrogen atom in the ground state are excited by monochromatic light of energy 12 1 eV The spectral lines emitted by hydrogen according to Bohr s theory will be CBSE PMT 1992 a one three My b two d four 1 81 residing in a

T Y B Sc I Physical Chemistry 8 The half life period of a radioactive element is 120 days After 600 days one gram of the element will reduce to 41 g b The unit of a rate of reaction is a 5 1 b mol s The order of the a 0 16 d g 6 mol 1 1

5 In Bohr series of lines of hydrogen spectrum the third line from the red end corresponds to which one of the following inter orbit jumps of the electron for Bohr orbits in an atom of hydrogen a 32 c 4 1 5 5 2 d 2 5 length of a tennis ball of mass 60g

97 For which of the following the radius will be same as for hydrogen atom having n 1 a He n 2 ran Be n 2 b Li2 n 2 d Li n 3 her of electrons with the azimuthal quantum

3 K 4 Rb 88 Consider the following transformation X n X 9 X X2 9 9 Then correct relation between n and n is 1 n n 2 n 2xn 3 2xn n

The approximate quantum number of a circular orbi diameter 20 6 nm of the hydrogen atom according Bohr s theory is Mxm a 10 c 12 www 14 d 16

The energy needed to remove one electron from unipositive ion is abbreviated as A 1st I P B 3rd I P D 1st E A 2nd 1 P The radius of pati

4 15 The sub shell that comes after f sub sell is called g subshell The number of g sub orbitals in g sub shell and the total number of orbitals in the principal orbital respectively are Final Results 0 10 and 25

5 a The wavelength in a vacuum of electromagnetic radiation is 275 nm What is the frequency of this radiation b What is the energy in joules of a photon in air of radiation with a wavelength of 589 nm h 6 626 x 10 4 Js c 2 998 x 108 m sl

A stream of electrons from heated filament was passed between two charged plates kept at a potential difference V esu If e and m are charge and mass of an electron respectively then the value of h 2 where A is wavelength associated with electron wave is given by 1 2meV 2 meV 3 2 mev 4 meV For a linear plot of log x m versus log p in a Freundlich absorption isotherm which of the following statements is correct k and n are constants

In a hydrogen spectrum if electron moves from 6th to 2nd orbit by transition in multi steps then find out the number of lines in spectrum Total number of line 4 3 2 1 10 n n n 1 6 2 4 1 4 5 2 2 or Total number of lines 2 A certain electronic transition from an excited state to Ground state of the Hydrogen atom in one or more steps gives rise of 5 lines in the ultra violet region of the spectrum How many lines does this transition produce in the Infra red region of the spectrum 5 Lines i a 10

A radioactive isotope having a half life of 3 days was received after 12 days It was found that there were 3 gm of the isotope in the container The initial mass of the isotope in gm when container was packed

1 For a hypothetical hydrogen like atom the potential energy of the system is given by U r where r is the distance between the two particles If Bohr s model of quantization of angular momentum is applicable then velocity of particle is given by 1 V 2 V 3 V Ke 87 m 24 Ke m 8Ke m 4 V 24 Ke n m Ke

If the rate constant of a chemical reaction at 500K 700K are 0 02s 1 and 0 07 s 1 respectively its activation energy is In7 1 9 In2 0 7 R 8J mol K O 1680 kJ mol 16800 J mol 1680 cal mol O 16 8 kcal mol

The amount of energy when million atoms of iodine are completely converted into I ions in the vapour state according to the equation 1 8 er is 4 9x10 J Calculate the electron gain enthalpy of iodine in terms of eV atom A 3 06 B 3 06 C 126

Calculate the rate of condensation on a 1 5 by 1 5 m vertical plate maintained at 40 and exposed to saturated water vapor at 55 F h fg 2376 kJ kg at 55 F A vertical plate 40 by 40 cm is exposed to saturated vanor ammonia at 38

P is the probability of finding the 1s electron of hydrogen atom in a spherical shell of infinitesimal thickness dr at a distance r from the nucleus The volume of this shell is 4tr dr The qualitative sketch of the dependence of P on ris a P 0 c P r b P 0 d P 0 1 r

d 3 84x10 m The wavelength of radiation emitted when electron falls from 4th Bohr s orbit to 2nd in H atom is RH 1 09678x10 7m a 972 nm c 243 nm 5 The energy of electron 486 nm d 182 nm

In which of the following arrangements the sequence is not strictly according to the property written against it A B C D CO SiO SnO PbO increasing oxidising power NH3 PH3 AsH3 SbH3 increasing basic strength HF HCI HBr HI increasing acidic strength B C O N increasing first ionisation enthalpy

1 Problem about Nearly Free electron in One Dimension Electrons of mass m are confined to one dimension A weak periodic potential described by the Fourier series V x Vo Vi cos 2xx a V cos 4xx a is applied a Under what conditions will the nearly free electron approximation work Assuming that the condition is satisfied sketch the three lowest energy bands in the first Brillouin zone Number the energy bands starting from one at the lowest band b Calculate to first order the energy gap at k a between the first and second band and k 0 between the second and third band

Consider that azimuthal quantum number 7 is having n 1 values i e whole number from o to n instead of 0 to n 1 value for any value of principle quantum number n If all the current laws of electronic configuration are applicable then what will be the spin only magnetic moment of Fe2 ion A 2 82 BM B 4 89 BM C 3 87 BM D 1 73 BM

3 In Kjeldahl s method of estimation of nitrogen nitrogen is quantitatively converted to ammonium sulphate It is then treated with standard solution of alkali The nitrogen which is present is estimated as 1 N 2 NO 3 NH

C Molecular formula of starch can be represented as C6H1005 n If the gold number of one such starch molecule is 12 96 and 0 01 millimoles of the above starch are required to be added to 10ml of gold sol to prevent coagulation by 1ml of 10 sodium chloride solution then calculate the value of n

Q1 Tick Mark the correct answer 1 In atomic absorption the sample is and excited by heat energy generated by a vaporised flame c quantised lamp b atomised burner d ionized furnace Atomic absorption is primarily used for the determination of in a sample

3 NO 4 HNO 1 Air 2 NH 10 The order of increasing reactively of the following compounds towards HCI will be 1 CH CH 11 2 CH C CH 3 CH CH CHCH 1 1 2 3 Ans 2 The mo 2 1 3 2 3 3 2 1 If th 4 2 1 3

4 Square planar Diamagnetic 125 The hardest lanthanide is 1 La 2 Gd 3 Sm 4 Yb 126 Which of the following can not exist together in aqueous solution 1 HgCl and SnCl 2 HgCl and SnCl 3 SnCl4 and FeCl3 4 SnCl4 and PbCl 127 Which of the following is the correct order of increasing field strength of ligands to form coordination compounds 1 SCN F CN C 0 2 F SCN C 0 CN 3 CN C 0 SCN F 4 SCN F C 02 CN 128 Alum helps in purifying water by 1 forming Si complex with clay particles 2 sulphate part which combines with the dirt and removes it 3 aluminium which coagulates the mud particles 4 making mud water soluble 129 Among the following surfactant molecules the surfactant that forms micelles in aqueous solution at the lower CMC at ambient condition is 1 CH3 CH 15N CH3 3Br 2 CH CH OSO Nat 3 CH3 CH COO Na 4 CH3 CH2 11N CH3 3Br 130 Which one of the compound does not decolourised an acidified solution of KMnO4 1 S0 2 FeCl3 3 H 0 4 FeSO4 131 Which ore contains both iron and copper 1 Cuprite 2 Chalcocite 3 Chalcopyrite 4 Malachite 132 Which one of the following compounds on hydrolysis yield hydrogen peroxide 1 HNO3 2 H P 0 3 H S 08 4 H S 06 133 The formula of exhausted permutit is 1 K Al Si 0 XH O 2 CaAl2Si O8 xH O 3 Na Al Si 0 xH O 4 CaB Si 0g xH O 134 For a tetrahedral complex MCI the spin only magnetic moment is 3 83 B M The element M is 1 Co 2 Cu

In an X ray experiment different metals are used as the target In each case the frequency v of the radiation produced is measured If Z atomic number which of the following plots will be a straight line A v against Z B 1 v against Z C against Z J y against

Among the following irfactant molecules the surfactant that forms micelles in aqueous solution at the lower CMC at ambient condition is 1 CH CH 15N CH3 3Br 2 CH CH 11OSONa neet prep For a tetrahedral complex MCI the spin only magnetic moment is 3 83 B M The element M is 1 Co 2 Cu High Yielding Test Series Part Test 6 Pa Contact Number 9667591930 852752171

Ejection of the photoelectron from metal in the photoelectric effect experiment can be stopped by applying 0 5 V when the radiation of 250 nm is used The work function of the metal is A 4 eV B 4 5 eV C 5 eV C 550X

The ratio of area of orbit of first excited state of electron to the area of orbit of ground state for hydrogen atom will be A 16 1 B 4 1 C 8 1 BIOLOGY D 1 8

The wave function for an electron in a hydrogen atom is y Ne Here r is the distance from the distance from the nucleus to the electron and a is Bohr radius Calculate the normalization factor N 1 2 A za B 1 a 1 2 C B 1 7

Which of the following is not permissible set of quantum numbers O n 5 1 4 m 0 s On 4 1 0 m 0 s N O n 3 1 1 m 1 s O n 2 1 0 m 1 s 2 2 1 2 12

A 4 by 4 m horizontal heater is placed in room air at 15 C Both the top and the bottom surfaces are heated to 50 C Estimate the total heat loss by free convection A horizontal plate uniform in temperatura ot 100K har 41

Which transition emits photon of maxim frequency 1 second spectral line of Balmer series 2 second spectral line of Paschen series 3 fifth spectral line of Humphery series 4 first spectral line of Lymen series