200k views
5 votes
In which of the following is number of electrons the ion contains given correctly? A. H+ has 1 electron. B. Br- has 34 electrons. C. Al3+ has 16 electrons. D. Ca2+ has 18 electrons

2 Answers

5 votes
The correct answer would be D. Ca^2+ has 18 electrons. This is because 2+ means that 2 electrons have been removed, and Ca starts out with 20 electrons. As 20 - 2 = 18 electrons, D is the correct answer.

Hope this helps!
User Evgeniy Mironov
by
8.5k points
1 vote

Answer: The correct answer is Option D.

Step-by-step explanation:

Number of electrons that are present in an atom is determined by the electronic configuration of that atom.

If an ion is carrying a positive charge, it means that the atom has lost electrons and if an ion is carrying a negative charge, it means that the atom has gained electrons.

For the given options:

Option A: The atomic number of hydrogen atom is 1 and the electronic configuration for
H^+ ion will be:
1s^0

Thus, this atom does not have any electrons.

Option B: The atomic number of bromine atom is 35 and the electronic configuration for
Br^- ion will be:
1s^22s^22p^63s^23p^64s^23d^(10)4p^6

Thus, this atom has 36 electrons.

Option C: The atomic number of aluminium atom is 13 and the electronic configuration for
Al^(3+) ion will be:
1s^22s^22p^6

Thus, this atom has 10 electrons.

Option D: The atomic number of calcium atom is 20 and the electronic configuration for
Ca^(2+) ion will be:
1s^22s^22p^63s^23p^6

Thus, this atom has 18 electrons.

Hence, the correct answer is option D.

User Tilpner
by
8.0k points