1. ATOMIC STRUCTURE PREVIOUS EAMCET BITS. 1) 25 : 9 2) 5 : 3 3) 9 : 25 4) 3 : 5 Ans: 1 Sol: According to de-broglie equation h

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1 . ATOMIC STRUCTURE PREVIOUS EAMCET BITS. The wavelengths of electron waves in two orbits is 3 :. The ratio of kinetic energy of electron will be (E-009) ) : 9 ) : 3 3) 9 : ) 3 : Sol: According to de-broglie equation h λ= But λ: λ = 3: nv v:v = :3 K.E = mv KE : KE = :3 = :9. With increases in principal quantum number n the energy difference between adjacent energy levels in hydrogen atom (M-009) ) increases ) decreases 3) remain constant ) decreases for lower values of n and increases for higher values of n Ans: 3.6 Sol: En = ev n As value of n increases the energy difference between adjacent levels decreases. 3. An electronic transition in hydrogen atom results in the formation of H α line of hydrogen in Lyman series, the energies associated with the electron in each of the orbits involved in the transition (in kcal mol ) are (E-008) ) ) ) 78., 3.83 ) 78., 9.6 Ans: Sol: H α line in Lyman series mean electron transition is from n = to n = orbit E = = 33.6 k.cal mole 33.6 E = = 78. k.cal mole. The velocities of two particles A and B are 0.0 and 0.0 ms respectively. The mass of B is five times the mass of A. The ratio of their de-broglie s wavelength is (E-008) ) : ) : 3) : ) : h Sol: λ= mv h λ λ A = λ B = m 0.0 m 0.0 λ A m 0.0 = = : λ B m 0.0. The wavelength (in A ) of an emission line obtained for Li + during electronic transition from n = to n = is (R = Rydberg constant) (M-008)

2 ) 3R ) 7R 3) 3R ) Ans: + 7R Sol: For Li v = 3 R = λ= 7R 6. Match the following List I List II nh A) mvr = π i) Paschen series B) Infra-red ii) Electron total energy n C) λ= p iii) de-broglie equation e D) r iv) Schrodinger equation v) Bohr s equation 7R (M-008) A B C D A B C D ) v ii iii i ) iii ii v iv 3) v i iii ii ) iv i ii iii nh Sol: A) mvr = Bohr s equation A (v) π B) Infrared - Paschen series B (i) n C) λ= - de-broglie equation C = iii p e D) - total energy of electron D - ii r 7. What is the wave number of th line in Balmer series of Hydrogen spectrum? ( R=,09,677cm ) (M-007) ),630 cm ),360 cm 3),730 cm ),37 cm Ans: Sol: th line in Balmer series mean electron transition from 6 th orbit to nd orbit. = = = γ= =,37 cm 36

3 3 8. The atomic number of an element M is 6. How many electrons are present in the M-shell of the element in its M 3+ state? (M-007) ) ) 3) ) 3 Ans: Sol: Z= 6= Fe= ssp3s3ps3d s s p 3s 3p 3d Fe = K L M Electron in M shell = 3 9. The wavelength of a spectral line emitted by hydrogen atom in the Lyman Series is 6 R cm. What is the value of n? (R = Rydberg constant) (E-007) ) ) 3 3) ) Sol: Equation for Lyman series v R = = n λ R = R 6 n = = n 6 6 n = 0. The maximum number of sub levels, orbitals and electrons in N shell of an atoms respectively (E-007) ),, 3 ), 6, 30 3), 6, 3 ), 3, 6 Sol: N shell has four (s, p, d, f) sub levels N shell has 6 orbitals (s, 3p, d, 7f) N shell has 3 electron (6 x = 3). The energy of a photon is 3 x 0 - ergs, Its wavelength in nm (E-006) ) 66 ) 3 3) 66. ) 6.6 Sol: hc hc E = λ= λ E erg sec 3 0 cms = 3 0 erg λ= cm = 66 nm. What is the correct order of spin only magnetic moment (in BM) of Mn + and V + is (E - 006) + ) Mn + + > V > Cr + ) V + > Cr + > Mn + 3) Mn + + > Cr > V + ) Cr + > V + > Mn Spin only magnetic moment = n( n+ ) B.M N = number of unpaired electron Magnetic moment is proportional to number of unpaired electron.

4 Number of unpaired electron in Mn + = Number of unpaired electron in Cr + = Number of unpaired electron in V + = 3. The angular momentum of an electron present in the excited state of Hydrogen is.h π electron present in ) Third orbit ) Second orbit 3) Fourth orbit ) Fifth orbit nh.h Angular momentum = π = π n = 3. The (M-006). What is the wavelength (in m) of a particle of mass ( ) ms? h j.s g moving with a velocity of = (M-00) ) ) ) 0 ) 0 9 m = g 3 = kg 3 v= 0 ms de-broglie equation 3 h λ= = = 0 m 3 3 mv What is the lowest energy of the spectral line emitted by the hydrogen atom in the Lyman series? (h=plank constant; C=Velocity of light; R=Rydberg constant). (M-00) ) hcr ) hcr 3) 3hcR ) 7hcR 36 3 Lyman series equation = v = = R n λ Lowest energy is emitted when electron moves from n= to n = 3 v = R = R 3 3hcR E = hν= hcv= hc R = 6. Assertion(A):The spin only magnetic moment of SC 3+ is.73 BM. Reason(R): The spin only magnetic (in BM) of an ion is equal to n( n+ ) where n is the number of unpaired electrons present in the ion. The correct answer is : ) Both (A) and (R) are true and (R) is the correct explanation of (A) ) Both (A) and (R) true and (R) is not the correct explanation of (A) 3) (A) is true but (R) is not true ) (A) is not true but (R) is not true (M-00)

5 Ans: 3 Sc + has zero unpaired electron. So its spin only magnetic moment in BM is zero Spin only magnetic moment μ s = n( n+ ) Where n = no of unpaired electron 7. An electron is moving in Bohr s orbit. Its debrogile wavelength is λ. What is the circumference of the fourth orbit? (E-00) ) / λ ) λ 3) λ ) / λ π r = nλ n = πr = λ 8. The atomic numbers of elements X,Y and Z are 9, and respectively. The number of electrons present in the M shells of these elements follow the order. ) Z>X>Y ) X>Y>Z 3) Z>Y>X ) Y>Z>X 6 6 X = 9= s s p 3s 3p s Mshell 6 6 Y= = ssp3s3p3ds Mshell 6 6 Z= = s s p 3s 3p 3d s Mshell (E-00) Z > Y > X 9. Which of the following pair of ions have same paramagnetic moment? (E-00) ) Cu,Ti + + ) Mn,Cu + + 3) Ti,Cu ) Ti, Ni Ans: Cu ( 3d ) and Ti ( 3d ) have one unpaired electron each. So they have same para magnetic moment. 0. Which of the following elements has least number of electrons in its M shell (E-00) ) K ) Mn 3) Ni ) Sc 6 6 K = 9= s s p 3s 3p s k has only 8 electron in M shell M. The values of four quantum numbers of valence electrons an element X n =,= 0,m= 0, s =. The element is (M-00) ) K ) Ti 3) Na ) Sc The given quantam numbers indicate the valence electron is in s orbital. Valance electron of K is in s orbital. An element has electrons in K shell, 8 electrons in L shell, 3 electrons in M shell and one electron in N shell. The element is (M-00) ) Cr ) Fe 3) V ) Ti

6 Electronic configuration of given element, 8, 3,. This indicate the element is chromium 3. If the wave length of an electromagnetic radiation is 000 A. What is the energy in ergs? (E-003) ) ) ).97 0 ) hc E = λ erg sec 3 0 cm sec = cm = erg. If the electron of a hydrogen atom is present in the first orbit, the total energy of the electron is (E-003) ) e /r ) e /r 3) e /r ) e /r Total energy of electron in st e orbit = r. Which one of the following expressions represent the electron probability function (D) (M-003) ) πrdrψ ) πr drψ 3) πr drψ ) πrdrψ D function is = πr.dr. ϕ = probability function 6. The total number of electrons present in all the S orbitals, all the P orbitals and all the d orbitals of caesium ion are respectively. (M-003) ) 6, 6, 0 ) 0,,0 3) 8,, ), 0, 3 Ans: C s = = = s s p 3s 3p 3d s p d s p Total s electron = 0 Total p electron = Total d electron = 0 7. The atomic number of an element is 3. What is the total number of electrons present in all the P- orbitals of the ground state atom of the element (M-003) ) 6 ) 3) 7 ) ( Z= 3ssp3s3p3d ) sp P electron = 7 8. The calculated magnetic moment (in Bohr magneton) of Cu + ion is (E-00) ).73 ) 0 3).6 ) 3. Cu + = Ar 3d 9 6

7 μ s = n( n+ ) = 3 =.73B.M n = number of unpaired electrons 9. Which one of the following statement is not correct? (E-00) ) Rydberg's constant and wave number have same units ) Lyman series of hydrogen spectrum occur in the ultraviolet region h 3) The angular momentum of the electron in the ground state hydrogen atom is equal to π ) The radius of first Bohr orbit of hydrogen atom is.6 x 0-8 cm. Ans: Radius of st 8 orbit = cm Therefore is wrong answer 30. How many 'd' electrons are present in Cr + ion? (M-00) ) ) 3) 6 ) 3 Cr = [ Ar] s 3d Cr + = Ar 3d the number of d electrons = 3. Which one of the following statements is correct? (M-00) ) 's' orbital is spherical with two nodal planes ) The de Broglie wavelength ( λ ) of a particle of mass 'm' and velocity 'V' is equal to mv/h 3) The principal quantum number (n) indicates the shape of the orbital ) The electronic configuration of phosphorous is given by [Ne] 3s 3p x 3p y 3p z Ans: Electronic configuration of p is [ Ne] 3s 3px3py3p z Alternate is correct All other are wrong 3. Which one of the following ions exhibit highest magnetic moment? (E-00) ) Cu + ) Ti 3+ 3) Ni + ) Mn + Ans: Cu + = Ar s 0 3d 9 unpaired electron Ti 3+ = Ar s 0 3d unpaired electron Ni + = Ar s 0 3d 8 unpaired electrons Mn + = Ar s 0 3d unpaired electrons Magnetic moment increases with increase in number of unpaired electron. Mn + has more number of unpaired electron it has highest magnetic moment. 7

8 8 33. The energy of an electron present in Bohr s second orbit of hydrogen atom is (E-00) ) -3J atom - ) -38kJ mol - 3) -38 J mol - ) -6kJ mol - Ans: 3 En = kjmole n 3 E = = 38kJ mole 3. In the ground state, an element has 3 electrons in its "M-shell". The element is (E-00) ) Copper ) Chromium 3) Nickel ) Iron Ans: 6 6 Cr = s s p 3s 3p 3d s Mshell Cr has 3 electron in M shell 3. Which one of the following is a diamagnetic ion? (M-00) ) Co + ) Cu + 3) Mn + ) Sc 3+ Ans: Co + = Ar s 0 3d 7 Mn Sc Cu + = Ar s 0 3d 3+ = Ar s 0 3d 0 + = Ar s 0 3d 9 3 Diamagnetic ion should have no unpaired electrons only Sc + in has all the electron paired. So it in diamagnetic. 36. Which one of the following pairs of ions have the same electronic configuration? (M-00) ) Cr +3, Fe +3 ) Fe +3,Mn + 3) Fe +3,CO +3 ) Sc +3,Cr +3 Ans: Fe 3+ = [ Ar] 3d Mn + = [ Ar] 3d 37. The atomic number (Z) on an element is. In its ground state how many electrons are present in the "N" shell? ) 3 ) 3) ) 3 Ans: (M-00) Z = 6 6 s s p 3s 3p s 3d N = th orbit In th orbit electrons are present 38. What are the values of n and n respectively for H β line in the Lyman series of hydrogen atomic spectrum? ) 3 and ) and 3 3) and 3 ) and (E-000)

9 H β line is formed when e jumps from 3 rd orbit to st orbit in lyman series n = n = How many electrons are present in the M-shell of an atom of the element with atomic number Z=? (E-000) ) ) 6 3) ) 3 Ans: 6 6 Z = = s s p 3s 3p s 3d M shell = 3 rd orbit In M shell 3 electron are present 0. The probability of finding an electron in an orbital is approximately? (M-000) ) 9% ) 0% 3) 60% ) % The probability of finding an electron in an orbital is approximately 9%.. What is the wavelength of H β line the Balmer series of hydrogen spectrum? (R = Rydberg constant) (M-000) ) 36/R ) R/36 3) 3R/6 ) 6/3R Ans: n = n = υ= = R n λ n υ= R υ= R 6 3 3R υ= R υ= λ= = υ 3R 9

Chemistry (

Chemistry ( Question 2.1: (i) Calculate the number of electrons which will together weigh one gram. (ii) Calculate the mass and charge of one mole of electrons. Answer 2.1: (i) Mass of one electron = 9.10939 10 31