| Clue | Source | Date |
|---|---|---|
| They don't mix very well | Newsday | 23 Sep 2023 |
| Argon and neon, e.g | Wall Street Journal | 06 Jun 2020 |
| Nonreactive elements, and what are hidden in the answers to 17-, 26-, and 47-Across | ||
| They seldom mix | ||
| They don't react well | ||
| Helium, neon, argon, etc. |