Question

The ion of an element has 2 positive charge. Mass number of the atom is 40 and the number of neutron is 20. What is the number of electron in the ion?​

Answer 1

From mass number and number of neutrons, we can calculate number of protons or electrons which is 13 (mass number - number of neutrons). Hence, the electronic configuration of this element would be 2, 8, 3. In order to become stable it would lose the last 3 electrons and gain 3 positive charges as given in the question. So, the resultant ion is left with 10 electrons. The element here is Al (aluminium).

Hence correct option is (B).

Answer 2

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