| 1 | A | B | C | D | E | F | G |
| --- | --- | --- | --- | --- | --- | --- | --- |
| 2 | Roentgenium - Stability and half-lives |  |  |  |  |  |  |
| 3 | Isotope | Half-life | Half-life | Half-life | Decay mode | Discovery year | Discovery reaction |
| 4 | Isotope | Recent publications | Ref | NUBASE 2016 | Decay mode | Discovery year | Discovery reaction |
| 5 | 272Rg | 3.8 ms | - | 4.5 ms | α | 1994 | 209Bi(64Ni,n) |
| 6 | 274Rg | 14 ms | - | 29 ms | α | 2004 | 278Nh(—,α) |
| 7 | 278Rg | 4.2 ms | - | 8 ms | α | 2006 | 282Nh(—,α) |
| 8 | 279Rg | 90 ms | - | 180 ms | α | 2003 | 287Mc(—,2α) |
| 9 | 280Rg | 4.6 s | - | 4.3 s | α, EC | 2003 | 288Mc(—,2α) |
| 10 | 281Rg | 17 s | - | 24 s | SF, α | 2010 | 293Ts(—,3α) |
| 11 | 282Rg | 1.7 min | - | 1.6 min | α | 2010 | 294Ts(—,3α) |
| 12 | 283Rg | 5.1 min | - | — | SF | 1999 | 283Cn(e−,νe) |
| 13 | 286Rg | 10.7 min | - | — | α | 1998 | 290Fl(e−,νeα) |

Question: How many isotopes of roentgenium have been reported with masses of 272, 274, 278–283, and 286?
Answer: Nine different isotopes of roentgenium have been reported with masses of 272, 274, 278–283, and 286.