(108Hs) is a synthetic element, and thus a standard atomic weight cannot be given. Like all synthetic elements, it has no stable isotopes. The first isotope to be synthesized was 265Hs in 1984. There are 12 known isotopes from 263Hs to 277Hs and 1–4 isomers. The most stable isotope of hassium cannot be determined based on existing data due to uncertainty that arises from the low number of measurements. The confidence interval of half-life of 269Hs corresponding to one standard deviation (the interval is ~68.3% likely to contain the actual value) is 16 ± 6 seconds, whereas that of 270Hs is 9 ± 4 seconds. It is also possible that 277mHs is more stable than both of these, with its half-life likely being 110 ± 70 seconds, but only one event of decay of this isotope has been registered as of 2016.[1][2].
I don't know what the problem is, but here are some rues to help you out:
All non-zero figures are significant
When a zero falls between non-zero digits, that zero is significant.
When a zero falls after a decimal point, that zero is significant.
When multiplying and dividing significant figures, the answer is limited to the number of sig figs equal to the least number of sig figs in the problem.
When adding and subtracting, the answer is limited to the number of decimal places in the number with the least number of decimal places.
The reason for the high melting and boiling temperatures is the hydrogen bonding between water molecules that causes them to stick together and to resist being pulled apart which is what happens when ice melts and water boils to become a gas
