| H |
| Gas |
| Light gas |
| Light element |
| #1 on a table |
| Most of water |
| Phish "I Am ___ |
| Lightest element |
| Element in water |
| No. 1 on the table |
| 1 in a table setting |
| Most abundant element |
| Rocket fuel component |
| It's always number one |
| One on a certain table |
| Lightest known substance |
| No 1 in the periodic table |
| Deuterium is an isotope of it |
| First item on a certain table |
| Most abundant substance in the universe |
| Chemical element with atomic no. 1 in the periodic table |