Question

Which of the following atoms and ions is (are) isoelectronic with S²+: Si4+, Cl³+, Ar, As³+, Si, Al³+?

a) Si⁴+, Cl³+, As³+
b) Si, Al³+, Ar
c) Si₄+, Cl³+, Si
d) Si, Ar, Al³+

Answer 1

The atoms and ions isoelectronic with S²+ are those with 14 electrons. Si⁴+, Cl³+, and Al³+ each have 14 electrons and are therefore isoelectronic with S²+.

Step-by-step explanation:

The question asks which atoms and ions are isoelectronic with S²+. An atom or ion is isoelectronic with S²+ when it has the same number of electrons. The sulfur ion S²+ has 16 protons and, as a divalent cation, it would have 14 electrons which is the electron count of the noble gas neon (Ne).

Looking at the given options, we find that:

• Si⁴+ (silicon with a 4+ charge) has 10 electrons, which is isoelectronic with Ne.
• Cl³+ (chlorine with a 3+ charge) has 14 electrons, which is isoelectronic with Ar.
• Ar (argon) has 18 electrons, which is not isoelectronic with Ne.
• As³+ (arsenic with a 3+ charge) has 33 - 3 = 30 electrons, not isoelectronic with Ne.
• Si (neutral silicon) has 14 electrons, which is not isoelectronic with Ne.
• Al³+ (aluminum with a 3+ charge) has 10 electrons, which is isoelectronic with Ne.

Therefore, the correct answer is Si⁴+, Cl³+, and Al³+.