Which of the following does not have a noble gas electron configuration? (or Which of the following is not isoelectronic with a noble gas?)

Q. Which of the following does not have a noble gas electron configuration? (or Which of the following is not isoelectronic with a noble gas?)

1. S^2-
2. Ba+
3. Al3+
4. Sb3-
5. Sc3+

Answer: Ba+