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Which of the following sets of quantum numbers represent an impossible arrangement -
n l m s
(C) If l=2, m -3
How many unpaired electrons are present in Ni2+ cation (atomic number = 28)
The electron configuration of Ni (atomic number 28) is 1s^2 2s^2 2p^6 3s^2 3p^6 3d^8 4s^2. When forming the Ni^2+ cation, the two 4s electrons are removed, leaving a configuration of 3d^8. The 3d subshell can hold 10 electrons, so there are 2 unpaired electrons in Ni^2+.
Number of unparired electrons in 1S2 2S2 2P3 is -
The given electronic configuration 1s^2 2s^2 2p^3 has 3 unpaired electrons, one each in the 2p orbitals. This is because the 2p subshell can hold a maximum of 6 electrons, and with 3 electrons present, there are 3 unpaired electrons.
The quantum numbers of four electrons are given below.
n m s
(C)
The correct order of decreasing energy will be electron 3 which has higher energy than 2 and in the order given.
E1 = 3s
E2 = 4s
E3 = 3d
E4= 3p
In Rutherford's alpha scattering experiment using gold foil, the kinetic energy of the alpha particle was 1.2 x 10-12J. For a head on collision, using the formula K.E. = x 2Ze2/r0 , what may be the magnitude of r0 [ The nuclear radius of gold, Z=79; = 9 x 109 new-ton/meter2 coulomb-2, e= 1.6x10-19 coulomb]
1.2 x 10-12= 9 x 109 x 2x79x[1.6x10-19]2 / r0
r0 = 9 x 79 x 256 x 2 x10-38 x 109 / 1.2 x 10-12 = 3 x 10-14m
The frequency of line spectrum of sodium is 5.09 x 1014 sec-1. Its wavelength (in nm) will be -[C= 3x108m/sec]
(C)
=0.5892 x 10-6 = 589.4 x 10-9m = 589nm
Consider an electron which is brought close to the nucleus of the atom from an infinite distance, the energy of the electron-nucleus system:
When an electron is brought closer to the nucleus, the potential energy of the electron-nucleus system decreases due to the attractive force between them. This decrease in potential energy results in a lower total energy of the system.
Using arbitrary energy units we can calculate that 864 arbitrary units (a.u.) are required to transfer an electron in hydrogen atom from the most stable Bohr's orbit to the largest distance from the nucleus
n = E= 0
n = 1 ; E= -864 Arbitrary units
The energy required to transfer the electron from third Bohr's orbit to the orbit n = will be-
The number of electrons in one molecule of CO2 are -
(A) One molecule of CO2 have 22 electrons.
The ion that is isoelectronic with CO is-
(A) CO 6+8 = 14
CN- 6+7+1 = 14
O2+ 8x2-1 = 15
O2- 8x2+1 = 17
N2+ 7x2-1 = 13
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