• # question_answer The number of electron and proton in the third alkaline earth metal ion will be [MP PET 2003] A) $\frac{e}{20},\,\,\frac{p}{20}$ B) $\frac{e}{18},\,\,\frac{p}{20}$ C) $\frac{e}{18},\,\,\frac{p}{18}$ D) $\frac{e}{19},\,\,\frac{p}{20}$

Third alkaline earth metal is calcium $_{20}C{{a}^{40}}$. No. of electron are 20 & No. of proton are 20; e/20, p/20.