SSC
CHEMISTRY
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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mass number
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atomic number
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atomic mass units
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Law of Conservation of Mass
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Detailed explanation-1: -The number of protons in the nucleus of the atom is equal to the atomic number (Z). 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.
Detailed explanation-2: -The number of protons in a nucleus is called the atomic number and always equals the number of electrons in orbit about that nucleus (in a nonionized atom). Thus, all atoms that have the same number of protons–the atomic number–are atoms of the same element.
Detailed explanation-3: -For example, a fluorine atom has 9 protons and 10 neutrons. Its atomic number is 9, while its atomic mass is 19 atomic mass units. So we can say that its atomic weight is 19, or its mass number is 19.