SSC
CHEMISTRY
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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Atomic Mass-Atomic Number
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Atomic Number-Atomic Mass
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Atomic Mass-Electrons
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none of these
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Detailed explanation-1: -The number of electrons in a neutral atom is equal to the number of protons. The mass number of the atom (M) is equal to the sum of the number of protons and neutrons in the nucleus. The number of neutrons is equal to the difference between the mass number of the atom (M) and the atomic number (Z).
Detailed explanation-2: -The atomic number of the element equals the number of protons. Calculating the number of neutrons then becomes atomic mass of the isotope minus the atomic number of the element equals the number of neutrons. For uranium-235, atomic number 92, the number of neutrons is 235-92=143, or 143 neutrons.
Detailed explanation-3: -To find the number of neutrons, subtract the number of protons from the mass number. number of neutrons=40−19=21.