This is a list of seasons of the National Hockey League (NHL), a professional ice hockey league, since its inception in 1917. The list also includes the seasons of the National Hockey Association (NHA), the predecessor organization of the NHL, which had several teams that would continue play in the NHL.he NHL continued the split-season and playoff format upon the winding up of the NHA organization. Except for the 1919â20 season, where there was no playoff because Ottawa won both halves of the season, the champion of the NHL has been the playoff champion.
The radioactive half-life for a given radioisotope is the time for half the radioactive nuclei in any sample to undergo radioactive decay. After two half-lives, there will be one fourth the original sample, after three half-lives one eight the original sample, and so forth. More on half-life discussion.
In addition to the four stable isotopes, thirty-one unstable isotopes of strontium are known to exist (see Table, below): the longest-lived of these are 90 Sr with a half-life of 28.9 years and 85 Sr with a half-life of 64.853 days.