| # | Symbol | Name | Atomic Mass | Category |
|---|---|---|---|---|
| 37 | Rb | Rubidium | 85.468 | Alkali Metals |
| 38 | Sr | Strontium | 87.62 | Alkaline Earth Metals |
| 39 | Y | Yttrium | 88.906 | Transition Metals |
| 40 | Zr | Zirconium | 91.224 | Transition Metals |
| 41 | Nb | Niobium | 92.906 | Transition Metals |
| 42 | Mo | Molybdenum | 95.95 | Transition Metals |
| 43 | Tc | Technetium | 98 | Transition Metals |
| 44 | Ru | Ruthenium | 101.07 | Transition Metals |
| 45 | Rh | Rhodium | 102.906 | Transition Metals |
| 46 | Pd | Palladium | 106.42 | Transition Metals |
| 47 | Ag | Silver | 107.868 | Transition Metals |
| 48 | Cd | Cadmium | 112.414 | Transition Metals |
| 49 | In | Indium | 114.818 | Post-Transition Metals |
| 50 | Sn | Tin | 118.71 | Post-Transition Metals |
| 51 | Sb | Antimony | 121.76 | Metalloids |
| 52 | Te | Tellurium | 127.6 | Metalloids |
| 53 | I | Iodine | 126.904 | Halogens |
| 54 | Xe | Xenon | 131.293 | Noble Gases |
18 elements