Timeline of chemical element discoveries Modern discoveries Modern discoveries

| Z | Element_ | Observed_or_predicted | Isolated_widely_known | Observer | First_isolator | Notes_ |
|---|---|---|---|---|---|---|
| 7 | Nitrogen | 1772 | 1772 | D. Rutherford | D. Rutherford | He discovered Nitrogen while he was studying at the University of Edinburgh. He showed that the air in which animals had breathed, even after removal of the exhaled carbon dioxide, was no longer able to burn a candle. Carl Wilhelm Scheele, Henry Cavendish, and Joseph Priestley also studied the element at about the same time, and Lavoisier named it in 1775-6. |
| 17 | Chlorine | 1774 | 1774 | W. Scheele | W. Scheele | Obtained it from hydrochloric acid, but thought it was an oxide. Only in 1808 did Humphry Davy recognize it as an element. |
| 25 | Manganese | 1774 | 1774 | W. Scheele | G. Gahn | Distinguished pyrolusite as the calx of a new metal. Ignatius Gottfred Kaim also discovered the new metal in 1770, as did Scheele in 1774. It was isolated by reduction of manganese dioxide with carbon. |
| 56 | Barium | 1772 | 1808 | W. Scheele | H. Davy | Scheele distinguished a new earth (BaO) in pyrolusite and Davy isolated the metal by electrolysis. |