SCIENCE
PHYSICAL SCIENCES
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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What is the mass number of an element that has 19 protons, 19 electrons, 20 neutrons
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20
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50
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39
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19
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Explanation:
Detailed explanation-1: -An element contains 20 neutrons in the nucleus and 19 electrons around it. it contains 19 protons and its atomic number is 19 and its mass number is 39.
Detailed explanation-2: -The element potassium has an atomic number 19 and a mass number is 39.
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