Question

monatomic ion with a charge of +2 has an electronic configuration of 1s22s22p63s23p6. This ion is a(n) . What is the chemical symbol of the noble gas this ion is isoelectronic with? . What is the formula of the ion?

Answer 1

Answer: The ion is $Ca^{2+}$. The chemical symbol of the noble gas this ion is isoelectronic with Kr.

Explanation:

The given electronic configuration is,

$M^{2+}:1s^22s^22p^63s^23p^6$

The number of electrons = 2 + 2 + 6 + 2 + 6 = 18 electrons

As the ion has a charge of +2 , that means it has lost two electrons so the the neutral element will have 2 more electrons i.e 18+2 = 20. The element has atomic number of 20 and the element will be Calcium with electronic configuration of

$M: 1s^22s^22p^63s^23p^64s^2$

Thus the symbol of ion is $Ca^{2+}$. the nearest noble gas with 18 electrons is Krypton with symbol Kr.