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?
The Correct Answer and Explanation is :
The ion with an electronic configuration of 1s² 2s² 2p⁶ 3s² 3p⁶ is a monatomic ion with a +2 charge. To analyze this further:
Step 1: Determining the Identity of the Ion
The electronic configuration 1s² 2s² 2p⁶ 3s² 3p⁶ corresponds to a neutral atom of argon (Ar), which has an atomic number of 18. Argon’s electron configuration is [Ne] 3s² 3p⁶, indicating that it has a total of 18 electrons.
When the ion has a charge of +2, it has lost two electrons, meaning it originally had 20 electrons but now has only 18 electrons. Therefore, the ion is Ca²⁺, which is the calcium ion with a +2 charge.
Step 2: Isoelectronic Noble Gas
The Ca²⁺ ion, having the same electron configuration as neutral argon (1s² 2s² 2p⁶ 3s² 3p⁶), is isoelectronic with argon (Ar). Isoelectronic means that the ion has the same number of electrons as the noble gas, argon, in this case.
Step 3: Formula of the Ion
The formula of the ion is Ca²⁺. This is because calcium (Ca) in its neutral state has 20 electrons (atomic number 20). When it loses two electrons to form a +2 charge, it becomes Ca²⁺.
Explanation
- Calcium (Ca), a metal, commonly forms a +2 cation by losing its two outermost electrons (in the 4s orbital), achieving a stable electron configuration resembling that of a noble gas.
- Noble gases have full electron shells, making them stable and non-reactive. In this case, the loss of two electrons from Ca results in a configuration identical to argon, which is a stable noble gas. Hence, Ca²⁺ is isoelectronic with argon (Ar), having the same electron configuration of 1s² 2s² 2p⁶ 3s² 3p⁶.