Calcium forms which ion?

Calcium forms which ion?

• A. Ca 2+
• B. Ca 3+
• C. Ca 1+
• D. Ca -

Answer: (A)

Calcium forms ions by losing its two outer electrons to reach a stable electron arrangement like a noble gas. The neutral atom has two valence electrons in the 4s orbital, so it most readily sheds them to become Ca2+. This +2 charge is the common and energetically favorable state for calcium in compounds such as CaCl2 or in body fluids as Ca2+. Gaining electrons to form a negative ion or removing more than two electrons would require breaking into a full inner shell or paying a much higher energy cost, which doesn’t happen under ordinary conditions.

Calcium forms ions by losing its two outer electrons to reach a stable electron arrangement like a noble gas. The neutral atom has two valence electrons in the 4s orbital, so it most readily sheds them to become Ca2+. This +2 charge is the common and energetically favorable state for calcium in compounds such as CaCl2 or in body fluids as Ca2+. Gaining electrons to form a negative ion or removing more than two electrons would require breaking into a full inner shell or paying a much higher energy cost, which doesn’t happen under ordinary conditions.