ECAT Chemistry Online Test With Answers

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ECAT Chemistry Online Test

Sr. # Questions Answers Choice
1 Elements have the tendency to attain 8 electrons in their valence shell. This is known as Octer rule Hunds rule Pauli exclusion principle Auf ban principle
2 The driving force for making a bond is To attain noble gas electronic configuration To make soled compounds To make different compounds To make gaseous substances
3 Which of the following molecules has a net dipole moments CO<sub>2</sub> CS<sub>2</sub> SO<sub>2</sub> CCI<sub>4</sub>
4 Which of the following molecules has unpaired electrons in anti-bonding molecular orbitals? O<sub>2</sub> N<sub>2</sub> Br<sub>2</sub> F<sub>2</sub>
5 The force which holds the atoms together to form a compound is called A chemical bond Van der waal's force Dispersion force London force
6 The energy of ionization of an atom is the energy difference between orbital
7 Four d-orbitals contain four lobes while fifth contains only two lobes the orbital is dxy dxz dz<sup>2</sup> dx<sup>2</sup>- y<sup>2</sup>
8 When 6s orbital is complete then next electron goes to 6p 6d 5d 4f
9 The arrangement of subshells in the ascending order of their energy on complete filing of 4f subshell the entering electrons goes to 5s 5p 5d 5f
10 Electrons arranged in orbitals according to the increasing order of their n + l values, this rule is named as Hund's rule Heisenberg's principle Paulit exclusion principle Auf bau principle
11 The degenerate orbitals p-sub shell are 2 3 5 7
12 An orbital can accommodate maximum two electrons with opposite spins according to Heisenberg's principle Aufbau principle Hund's srule Pauli exclusion principle
13 Their e/m, ratio resembles with that of electrons Alpha rays Beta rays Gamma rays X-rays
14 The orbitals having n + l = 5 are 2p, 3d,3s 3p, 3d, 5s 3s, 4p, 4d 5s, 4p, 3d
15 For a 3P subshell the set of principle and azimuthal quantum number is n = 1 , l = 2 n = 3, l = 0 n = 3, l = 1 n = 1, l = 3
16 The total values of magnetic quantum number of subshell are five, the subshell is S-subshell P-subshell D-subshell F-subshell
17 The size of electronic shell is described by Azimuthal Q. no Magnetic Q.No Spin Q. No Principle Q. No
18 Schrodinger wave equation describes electron completely because It describes a set of four quantum number It describes the particle nature of electron It measures wavelength of electron It describes electron moving in specific orbit
19 The value of Plank's constant 'h' is 6.625 x 10<sup>-34</sup> 6.625 x 10<sup>-34</sup>J sec 6.625 x 10<sup>-34</sup>KJ 6.625 x 10<sup>-34</sup>K Cal
20 The uncertainty principle was stated only De Brogilie Heinsenberg Einstein Schrodinger
21 Plank's equations de Broglie's equations Heisenburg's equation None
22 The divisibility of atom was shown by Stoney J.J. Thomson Millikan Rutherford
23 The wave number of the line emitted is 109.678 x 105m-1in the Lyman series when electron transition occurs
24 Light emitted from a source has its wave length 500nm, then its wave number will be 2 x 10<sup>6</sup>m<sup>-1</sup> 2 x 10<sup>7</sup>m<sup>-1</sup> 5 x 10<sup>8 </sup>m<sup>-1</sup> 5 x 10<sup>9</sup>m<sup>-1</sup>
25 In the ground state of an atom the electron is present In the nucleus In the second shell Nearest to the nucleus Farthest from the nucleus
26 Splitting of spectral lines of the hydrogen atom under the influence or magnetic field is called Stark effect Zeeman effect Compton effect Photoelectric effect
27 The limiting line of Blamer series in hydrogen spectrum lies in Visible regions Ultraviolet region Infrared region x-rays region
28 When electron jumps from n2= 2,3,4,5,.... orbit to n1= 1 orbit in the hydrogen atom, the radiations emitted give the spectral lines Lyman series Blamer series Paschen series Brackett series
29 In the atomic emission spectrum the lines which appear bright, appear dark in absorption spectrum because The radiations emitted in emission spectrum are absorbed in absorption spectrum Atomic emission spectrum is continuous Atomic absorption spectrum is continuous Distance between the lines increases
30 Energy of electron in an orbit according to Bohr theory is negative due to Repulsion of electrons in the same orb At infinity energy is zero ad a traction towards nucleus decreases energy Electron has negative charge Product of positive nuclear charge and negative charge is negative
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