To determine which of the given atoms and ions are isoelectronic with [tex]\( S^{2+} \)[/tex], we need to understand that two species are isoelectronic if they have the same number of electrons.
- A neutral Sulfur (S) atom has an atomic number of 16, meaning it has 16 electrons.
- When sulfur loses 2 electrons to form [tex]\( S^{2+} \)[/tex], it will have [tex]\( 16 - 2 = 14 \)[/tex] electrons.
We now check the number of electrons for each of the given species:
(A) [tex]\( Si^{4+} \)[/tex]:
- A neutral Silicon (Si) atom has an atomic number of 14, so it has 14 electrons.
- When silicon loses 4 electrons to form [tex]\( Si^{4+} \)[/tex], it will have [tex]\( 14 - 4 = 10 \)[/tex] electrons.
- This is not isoelectronic with [tex]\( S^{2+} \)[/tex] (14 electrons).
(B) [tex]\( Cl^{3+} \)[/tex]:
- A neutral Chlorine (Cl) atom has an atomic number of 17, so it has 17 electrons.
- When chlorine loses 3 electrons to form [tex]\( Cl^{3+} \)[/tex], it will have [tex]\( 17 - 3 = 14 \)[/tex] electrons.
- This is isoelectronic with [tex]\( S^{2+} \)[/tex] (14 electrons).
(C) [tex]\( Ar \)[/tex]:
- A neutral Argon (Ar) atom has an atomic number of 18, so it has 18 electrons.
- This is not isoelectronic with [tex]\( S^{2+} \)[/tex] (14 electrons).
(D) [tex]\( As^{3+} \)[/tex]:
- A neutral Arsenic (As) atom has an atomic number of 33, so it has 33 electrons.
- When arsenic loses 3 electrons to form [tex]\( As^{3+} \)[/tex], it will have [tex]\( 33 - 3 = 30 \)[/tex] electrons.
- This is not isoelectronic with [tex]\( S^{2+} \)[/tex] (14 electrons).
(E) [tex]\( Si \)[/tex]:
- A neutral Silicon (Si) atom has an atomic number of 14, so it has 14 electrons.
- This is isoelectronic with [tex]\( S^{2+} \)[/tex] (14 electrons).
(F) [tex]\( Al^{3+} \)[/tex]:
- A neutral Aluminum (Al) atom has an atomic number of 13, so it has 13 electrons.
- When aluminum loses 3 electrons to form [tex]\( Al^{3+} \)[/tex], it will have [tex]\( 13 - 3 = 10 \)[/tex] electrons.
- This is not isoelectronic with [tex]\( S^{2+} \)[/tex] (14 electrons).
Therefore, the atoms and ions that are isoelectronic with [tex]\( S^{2+} \)[/tex] are:
- (B) [tex]\( Cl^{3+} \)[/tex]
- (E) [tex]\( Si \)[/tex]
Thus, the correct answer is:
(B) [tex]\( Cl^{3+} \)[/tex], (E) [tex]\( Si \)[/tex]
