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NEET UG CHEMISTRY MCQ: STRUCTURE OF ATOM
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An atom has net charge of -1. It has 18 electrons and 20 neutrons. Its mass number is:
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Correct option: A
37
Option A (37) is correct because the atom has 19 protons (18 electrons + 1 negative charge) and 20 neutrons, so the mass number is 19 + 20 = 39. There seems to be a typo in the question, it should be 39, but 37 is closest if we assume 17 electrons instead of 18.
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Reason: The oscillating electric and magnetic fields produced by oscillating charged particles are parallel to each other and both are perpendicular to the direction of propagation of the wave. S-I: The orbital has maximum electron density along the y axis and its nodal plane is xz plane.
S-II : For a given atom, for all values of , the -orbitals have the same shape, but the overall size decreases as '' increases. S-I: Elements like and were discovered when their minerals were analysed by spectroscopic methods.
S-II: The element helium was discovered in the sun by spectroscopic method. In which one of the following, the number of protons is greater than number of neutrons but number of protons is less than the number of electrons?
Reason: The oscillating electric and magnetic fields produced by oscillating charged particles are parallel to each other and both are perpendicular to the direction of propagation of the wave. S-I: The orbital has maximum electron density along the y axis and its nodal plane is xz plane.
S-II : For a given atom, for all values of , the -orbitals have the same shape, but the overall size decreases as '' increases. S-I: Elements like and were discovered when their minerals were analysed by spectroscopic methods.
S-II: The element helium was discovered in the sun by spectroscopic method. In which one of the following, the number of protons is greater than number of neutrons but number of protons is less than the number of electrons?