Chemistry - Atomic Structure and Periodic Properties of Elements
Exam Duration: 45 Mins Total Questions : 30
Bohr radius of nth orbit of an atom is given by the expression
- (a)
\(\quad r=\frac { { n }^{ 2 }{ h }^{ 2 } }{ 4{ \pi }^{ 2 }mZ{ e }^{ 2 } } \)
- (b)
\(\quad r=\frac { { n }^{ 2 }{ h }^{ 2 } }{ 4{ \pi }^{ 2 }mZ{ } } \)
- (c)
\(\quad r=\frac { { n }^{ 2 }{ h }^{ 2 } }{ 4{ \pi }^{ 2 }m{ e }^{ 2 } } \)
- (d)
\(\quad r=\frac { { n }^{ }{ h }^{ } }{ 4{ \pi }^{ 2 }m{ e }^{ 2 } } \)
The energy of one quantum of light with a wavelength of 6500 \(\mathring { A } \) (1\(\mathring { A } \)= 10-8 cm = 10-10 m)
- (a)
3X108ms-1
- (b)
3.06X10-19J
- (c)
6.02X10-20J
- (d)
9.04X10-24J
A drop of water is about 0.05ml. The density of water at room temperature is 1.0 g ml-1. Number of molecules present in a drop of water would be:
- (a)
1.675X1021 molecules
- (b)
1.675X1023 molecules
- (c)
1.675X1025 molecules
- (d)
1.675X1034 molecules
The uncertainity in the velocity of a cricket ball of mass 150g, when uncertainity in its position is of the order of 1 \(\mathring { A } \), would be
- (a)
\(\ge \) 3.5X 10-24 ms-1
- (b)
\(\ge \) 200ms-1
- (c)
\(\ge \) 400 ms-1
- (d)
\(\ge \) 600 ms-1
Energy of an electron in hydrogen atom is given by \(E=-\frac { 13.6 }{ { n }^{ 2 } } eV\). Which one of the following statements is true if n is changed from 1 to 4? Energy will
- (a)
decrease four times
- (b)
increase four times
- (c)
increase sixteen times
- (d)
decrease sixteen times
the proton and neutron are collectively called as
- (a)
deuterium
- (b)
positron
- (c)
meson
- (d)
nucleon
the correct configuration of copper with atomic number 29 is
- (a)
[Ar]4s1
- (b)
[Ar]4s2
- (c)
[Ar]3d104s1
- (d)
[Ar]3d104s2
The mass of an oxygen atoms is
- (a)
2.656X10-23g
- (b)
2.656X1023 g
- (c)
16 g
- (d)
32 g
The spectrum of He is expected to be similar to that of
- (a)
H
- (b)
Na
- (c)
He+
- (d)
Li+
It is not true that
- (a)
violet radiations have a longer wavelength than red radiations
- (b)
the energy of light with \(\lambda\)=650 nm is lower than with \(\lambda\)=500 nm
- (c)
spectrum of an atom is known as line spectrum
- (d)
the wavelength associated with an electron is lower than that of proton, if they are at the same speed
Which of the following expressions gives the de-Broglie relationship?
- (a)
\(\frac {h} {m\upsilon }=p\)
- (b)
\(\lambda=\frac {h} {m\upsilon}\)
- (c)
\(\lambda=\frac {h} {mp}\)
- (d)
\(\lambda m=\frac {\upsilon} {p}\)
The electronic configuration of an atom/ion can be defined by the following
- (a)
Aufbau principle
- (b)
Pauli's exclusion principle
- (c)
Hund's rule
- (d)
All the above
The quantum numbers for the designation 3d are:
- (a)
n=2; m=-3
- (b)
n=3; l=3
- (c)
n=4, l=1
- (d)
n=3, l=2
The number of neutrons in the element 94Be is?
- (a)
4
- (b)
5
- (c)
9
- (d)
13
how many unpaired electrons are there in Ni2+?
- (a)
0
- (b)
2
- (c)
4
- (d)
8
For the energy levels in an atom,which one of the following statements is correct?
- (a)
There are seven principal electron energy levels
- (b)
The second principal energy level has four sub-energy levels and contains a maximum of eight electrons
- (c)
The principal energy level N can have a maximum of 32 electrons
- (d)
The 4s sub-energy level has higher energy than 3d sub-energy level
The two electrons occupying an orbital are distinguished by
- (a)
principal quantum number
- (b)
azimuthal quantum number
- (c)
magnetic quantum number
- (d)
spin quantum number
For a sub-shell with azimuthal quantum number'l', the total values of magnetic quantum number m can be related to l as
- (a)
m=(l+2)
- (b)
m=(2l2 + 2)
- (c)
l=\(\frac { (m-1) } { 2 }\)
- (d)
l= 2m+1
Indicate which electronic configuration amongst following correctly represents SULPHUR atom?
- (a)
1s2 2s2 2p6 3s2 3p2 3d2
- (b)
1s2 2s2 2p6 3s2 3p2 4s2
- (c)
1s2 2s2 2p6 3s2 3p6 4s1 4p1
- (d)
1s2 2s2 2p6 3s2 3p4
The magnetic quantum number represents:
- (a)
Size of the orbital
- (b)
Spin angular momentum
- (c)
Orbital angular momentum
- (d)
Spatial Orientation of orbital
Which period contains maximum number of elements?
- (a)
7 th
- (b)
6 th
- (c)
4 th
- (d)
5 th
Atoms with high value of IE1 always have:
- (a)
Large atomic radius
- (b)
small atomic radius
- (c)
strongly bound valence electrons
- (d)
loosely bound valence electrons
Which of the following does not reflect the periodicity of elements
- (a)
Bonding behaviour
- (b)
Electronegativity
- (c)
Ionisation potential
- (d)
Neutron/proton ratio
Which among the following elements has the lowest value of IE1
- (a)
Pb
- (b)
Sn
- (c)
Si
- (d)
C
Which of the following pairs of elements belongs to same period of the periodic table?
- (a)
Na, Ca
- (b)
Mg, Sb
- (c)
Ca, CI
- (d)
Ca, Zn
Paulings electronegativity values for elements are useful in predicting
- (a)
Polarity of bonds in molecules
- (b)
position of elements in Electromotive series
- (c)
Co-ordination number
- (d)
Dipole moment of various molecules
The ionic species having largest size is:
- (a)
Li+(aq)
- (b)
Li+(g)
- (c)
Na+(aq)
- (d)
Rb+(aq)
The correct sequence of elements in the decreasing order of first ionisation energy is:
- (a)
Na > Mg > AI
- (b)
Mg > Na > AI
- (c)
AI > Mg > Na
- (d)
Mg > AI > Na
The wave number of first emission line of H-atom in Balmer series is equal to
- (a)
\(\frac{9R_H}{400}\)
- (b)
\(\frac{7R_H}{144}\)
- (c)
\(\frac{3R_H}{4}\)
- (d)
\(\frac{5R_H}{36}\)
What will be the uncertainty in velocity of a cricket ball of 100 g, if the uncertainty in its position is 1.65 Å?
- (a)
\(\frac{10^{-23}}{\pi}ms^{-1}\)
- (b)
\(\frac{6.6}{\pi}\times10^{-45}ms^{-1}\)
- (c)
\(1.65\times{10^{-43}}ms^{-1}\)
- (d)
\(\frac{10^{-26}}{\pi}ms^{-1}\)