The mass number (A) of an atom is the sum of the number of protons (p) and the number of neutrons (n). A = p + n. Given A = 27 and n = 14. So, 27 = p + 14, which means the number of protons (p) = 27 - 14 = 13. The number of protons determines the element and its atomic number (Z). Here, Z = 13. A neutral atom of this element would have a number of electrons equal to the number of protons, i.e., 13 electrons. However, the question is about an ion with a +3 charge. A positive charge means the atom has lost electrons. A +3 charge means it has lost 3 electrons. Number of electrons in the ion = Number of protons - Charge = 13 - 3 = 10.
The ion of an element has three positive change. Mass number of the atom is 27, and the number of neutrons is 14. What is the number of electrons in the ion?
Asked in WBPSC CS Prelims 2023 · Topic: Atomic Structure (Electronic Configurations of Multi-electron Atoms and Ions)
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