Platinum has 38 known isotopes, ranging from 78166Pt to 78203Pt. Of these, five are stable, one has a half-life of 6.5x1011 years, and all the others are relatively short, some being very, very short. I will show the longest lived, because you did not specify which one you were interested in.
78190Pt --> Alpha --> T1/2 = 6.5x1011 years --> 76186Os + 24He2+
All nuclear decay is spontaneous.
That depends on the nuclear decay type. For gamma decay, the identity does NOT change, but for alpha and beta, it does.
Natural chromium is stable and does not decay/
Matter can be made to undergo nuclear decay in reactors, but it is a process that occurs spontaneously in nature.
zeyta
what are the forms of nuclear decay
nuclear decay, such as alpha decay or beta decay.
Alpha nuclear decay
All nuclear decay is spontaneous.
yep, sure are
It stays the same. Temperature has no effect on the rate of nuclear decay.
That depends on the nuclear decay type. For gamma decay, the identity does NOT change, but for alpha and beta, it does.
I do not see an isotope of iridium that does alpha decay. There is an interactive link to isotopes below. (Perhaps I am missing it.)
gamma decay
radioactive decay
Natural chromium is stable and does not decay/
Matter can be made to undergo nuclear decay in reactors, but it is a process that occurs spontaneously in nature.