WBJEE Chemistry Questions & Answers

I want to give entrance exam of WBJEE (West Bengal Joint Entrance Examination) (Medical).Will you provide previous exam Questions & Answers of Chemistry for an idea?

[Kiran Chandar]

Below Questions & Answers of Chemistry subject of WBJEE (West Bengal Joint Entrance Examination) is given.

• The maximum number of electrons in an atom with l = 2 and n = 3 is


• 2
• 6
• 12
• 10
• The atomic weight of an element is 39. The number of neutrons in its nucleus is one more than the number of protons. The number of protons, neutrons and electrons respectively in its atom would be


• 19,19,20
• 20,19,19
• 20,19,20
• 19,20,19
• The uncertainty principle and the concept of wave nature of matter was proposed by ---------and respectively


• Planck, Heisenberg
• De Broglie, Heisenberg
• Heisenberg, De Broglie
• None of the above
• An electron has principal quantum number 3, the number of its: 1. Sub shell 2. Orbitals would be respectively


• 3 and 5
• 3 and 7
• 3 and 9
• 2 and 5
• The set of quantum numbers n=3, l= 0, m=0 and s= -1/2 belongs to the elemet


• Mg
• Na
• Ne
• F
• The number of possible spatial orientations of an electron in an atom is given by its


• spin quantum number
• spin angular momentum
• magnetic quantum number
• orbital angular momentum
• The wavelength associated with a moving particle is


• directly proportional to its mass
• directly proportional to its velocity
• inversely proportional to its momentum
• inversely proportional to its charge
• uncertainty principle gave the concept of


• probability
• an orbital
• both the above
• none of the above
• A moving particle may have wave motion, if


• its mass is very high
• its velocity is negligible
• its mass is negligible
• its mass is very high and velocity is negligible
• An element has electronic configuration 2,8,18,1. If its atomic weight is 63, then how many neutrons will be present in its nucleus


• 30
• 32
• 34
• 33


• A 3p orbital has


• two spherical nodes
• two non spherical nodes
• one spherical and one non spherical nodes
• one spherical and two non spherical nodes
• The number of electron in the nucleus of C-12 is


• 6
• 12
• 0
• 3
• The hybrid ions are iso electronic with


• Be
• Li
• He
• None of the above
• The atomic number of an element is always equal to


• atomic weight divided by 2
• number of neutrons in the nucleus
• weight of the nucleus
• electrical charge of the nucleus
• The ratio between the neutrons in C and Si with respect to atomic masses 12 and 28 is


• 2:3
• 3:2
• 3:7
• 7:3
• Energy of atomic orbitals in a particular shell is in the order


• s>p>d>f
• f>d>s>p
• p<d<f<s< li=""> </d<f<s<>
• none of the above
• Which of the following electron transitions will require the largest amount of energy in a hydrogen atom


• from n =1 to n = 2
• from n =2 to n = 3
• from n = infinite to n = 1
• from n =3 to n = 5
• The size of nucleus is measured in


• amu
• angstrom
• fermi
• cm
• For azimuthal quantum number l=3, the maximum number of electrons will be


• 2
• 6
• 0
• 14
• How man electrons can be accommodated in a sub- shell for which n =3 and l = 1


• 8
• 18
• 32
• 6
• From the given sets of quantum numbers the one that is inconsistent with the theory is


• n =3; l=2; m = -3; s = +1/2
• n =4; l=3; m = 3; s = +1/2
• n =2; l=1; m = 0; s = -1/2
• n =4; l=3; m = 2; s = +1/2
• When the azimuthal quantum number has a value of l =1, the shape of the orbital is


• unsymmetrical
• spherically symmetrical
• dumb -bell
• complicated
• The principal quantum number represents


• shape of an orbital
• distance of electron form nucleus
• number of electrons in an orbit
• number of orbitals in an orbit
• Ca has atomic No. 20 and atomic weight 40. Which of the following statements is not correct about Ca atom


• the number of electrons is same as the number of neutrons
• the number of nucleons is double of the number of electrons
• the number of protons is half of the number of neutrons
• the number of nucleons is double of the atomic number
• If electron, hydrogen, helium and neon nuclei are all moving with the velocity of light, then the wavelengths associated with these particles are in the order


• electron > hydrogen > helium > neon
• electron > helium > hydrogen > neon
• electron < hydrogen < helium < neon
• neon < hydrogen < helium < electron
• The shape of p- orbital is


• elliptical
• spherical
• dumb- bell
• complex geometrical
• The electrons would go to lower energy levels first and then to higher energy levels according to which of the following


• Aufbau principle
• Pauli's principle
• Hund's rule
• none of the above
• There is no difference between a 2p and a 3p orbital regarding


• shape
• size
• energy
• value of n
• The number of unpaired electrons in carbon atom in excited state is


• 1
• 2
• 3
• 4
• Cathode rays have


• mass only
• charge only
• no mass and no charge
• mass and charge both
• Neutron is a fundamental particle carrying


• a charge of +1 unit and a mass of 1 unit
• no charge and a mass of 1 unit
• no charge and no mass
• a charge of -1 and a mass of 1 unit
• the total number of electrons that can be accommodated in all the orbitals having principal quantum number 2 and azimuthal quantum number 1 is


• 2
• 4
• 8
• 6
• an atom has 2 electrons in K shell, 8 electrons in L shell and 6 electrons in M shell. The number of s -electrons present in that element is


• 6
• 5
• 7
• 10
• If an electron has spin quantum number of +1/2 and a magnetic quantum number of -1, it can not be presented in


• d- orbit
• p- orbit
• s- orbit
• f- orbit
• One orbital consists maximum electrons


• 8
• 18
• 2
• 12
• Neutron possesses


• positive charge
• negative charge
• no charge
• positive and negative both charges
• Anode rays were discovered by


• Goldstein
• J Stoney
• rutherford
• none of the above
• The atom of the element having atomic number 14 should have


• one unpaired electron
• two unpaired electrons
• three unpaired electrons
• four unpaired electrons
• According to Aufbau's principle, which ofthe three 4d, 5p and 5s will be filled with electrons first


• 4d
• 5p
• 5s
• all at the same time
• How many electrons can be fit into the orbitals that comprise the third quantum shell n = 3


• 2
• 8
• 18
• 32
• Number of neutrons in heavy hydrogen atom is


• 0
• 1
• 2
• 3
• Davisson and Germer's experiment showed that


• beta particles are electrons
• electrons come from nucleus
• electrons show wave nature
• none of the above
• The statements 1. In filling a group of orbitals of equal energy, it is energetically preferable to assign electrons to empty orbitals rather than pair them into a particular orbital. 2. When two electrons are placed in two different orbitals, energy is lower if the spins are parallel. are valid for


• Aufbau principle
• Hund's rule
• Pauli's exclusion principle
• uncertainty principle
• For the energy levels in an atom, which one of the following statements is correct


• there are seven principal electron energy levels
• the second principal energy level can have four sub energy levels and contains a maximum of eight electrons
• the M energy level can have maximum of 32 electrons
• the 4s sub energy level is at a higher energy than the 3d sub energy level
• Pauli's exclusion principle states that


• nucleus of an atom contains no negative charge
• electrons move in circular orbits around the nucleus
• electrons occupy orbitals of lowest energy
• all the four quantum numbers of two electrons in an atom cannot be equal
• Compared with an atom of atomic weight 12 and atomic number 6 , the atom of atomic weight 13 and atomic number 6


• contains more neutrons
• contains more electrons
• contains more protons
• is a different element
• When an electron jumps from L level to M level, there occurs


• emission of energy
• emission of X-rays
• absorption of energy
• emission of gamma rays
• The shape of s orbital is


• pyramidal
• spherical
• tetrahedral
• dumb bell shaped
• Which one of the following statements is incorrect


• in a given sub shell the electrons avoid entering the same orbital as far as possible
• in any single atom, no two electrons can be identical in all the four quantum numbers
• the electrons entering different orbitals of a sub shell have opposite spins
• none of the above
• When an electron drops from a higher energy level to a low energy level, then


• energy is emitted
• energy is absorbed
• atomic number increases
• atomic number decreases