Which of the following correctly represents the electronic distribution in the Mg atom?
  • 3, 8, 1
  • 2, 8, 2
  • 1, 8, 3
  • 8, 2, 2
Rutherford’s ‘alpha (α) particles scattering experiment’ resulted in the discovery of
  • electron
  • proton
  • nucleus in the atom
  • atomic mass
The number of electrons in an element X is 15 and the number of neutrons is Which of the following is the correct representation of the element?
  • \(_{15}^{31}\)X
  • \(_{16}^{31}\)X
  • \(_{15}^{16}\)X
  • \(_{16}^{15}\)X
The ion of an element has 3 positive charges. Mass number of the atom is 27 and the number of neutrons is What is the number of electrons in the ion?
  • 13
  • 10
  • 14
  • 16
The first model of an atom was given by
  • N. Bohr
  • E. Goldstein
  • Rutherford
  • J. J. Thomson
An atom with 3 protons and 4 neutrons will have a valency of
  • 3
  • 7
  • 1
  • 4
Which of the following statement is always correct?
  • An atom has equal number of electrons and protons.
  • An atom has equal number of electrons and neutrons.
  • An atom has equal number of protons and neutrons.
  • An atom has equal number of electrons, protons and neutrons.
Hydrogen exists in three isotopic forms, \(_{1}^{1}\)H, \(_{1}^{2}\)H, \(_{1}^{3}\)H known as protium, deuterium and tritium. Why are all the isotopes neutral in nature?
  • Since neutrons are neutral in nature hence isotopes are electrically neutral.
  • All the isotopes have one electron and one proton, hence they are neutral.
  • All the isotopes have one proton and one neutron, hence they are neutral.
  • Increasing number of protons in the isotopes make them neutral.
How many electrons are present in M-shell of an element with atomic number 20?
  • 5
  • 8
  • 12
  • 18
There are two atomic species X and Y, such that
  • X and Y are isobars.
  • X and Y have different chemical properties.
  • X and Y have different physical properties.
  • All of these.
An alpha particle is also known as:
  • subatomic particle
  • an unionised helium atom
  • a neutral particle
  • a doubly-charged helium ion
There are three isotopes of carbon which are named as C-12, C-13 and C-14 out of which C-12 is the most abundant isotope. In the given structures of 3 isotopes, what will be the composition of the nucleus?
  • C-12 : 6p + 6n, C-13 : 7p + 6n, C-14 : 8p + 6n
  • C-12 : 6p + 6n, C-13 : 6p + 7n, C-14 : 6p + 8n
  • C-12 : 6p + 6n, C-13 : 5p + 8n, C-14 : 7p + 7n
  • C-12 : 6p + 6n, C-13 : 12p + 1n, C-14 : 5p + 9n
Which of the following isotope is used in the treatment of blood cancer?
  • P-32
  • I-131
  • Co-60
  • any of these
Isobars do not differ in the number of
  • protons
  • electrons
  • neutrons
  • nucleons
The maximum number of electrons that can be accommodated in third shell ( n = 3) is:
  • 10
  • 2
  • 18
  • 8
Which of the following have equal number of neutrons and protons?
  • Chlorine
  • Hydrogen
  • Fluorine
  • Deuterium
The nucleons are
  • None of these
  • Protons and neutrons
  • Neutrons and electrons
  • Protons and electrons
The nucleus of an atom contains:
  • Protons only
  • Neutrons
  • Protons and neutrons
  • Electrons only
Which of the following arrangements of electrons represent magnesium (Mg)?
  • 2, 8, 2
  • 2, 8, 3
  • 2, 8, 1
  • 2, 8, 4
The charge on an electron is:
  • 1.6 x 10-6 Coulombs
  • 1.6 x 10-20 Coulombs
  • 1.6 x 10-16 Coulombs
  • 1.6 x 10-19 Coulombs
0 h : 0 m : 1 s

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