Answer:
No. of electrons = 18
No. of protons = 20
Step-by-step explanation:
The atomic number of Ca is 20. Thus, it contains 20 protons and 20 electrons.
One Ca atom loses 2 electrons to form Ca2+ ion.
Ca→Ca2+ + 2e
−
Hence, the number of electrons in Ca 2+ ion is 20−2=18.
Thus, 20 protons and18 electrons are present in Ca 2+