The answer to this question would be: 3.125%
Half-life is the time needed for a radioactive molecule to decay half of its mass. In this case, the strontium-89 is already gone past 5 half lives. Then, the percentage of the mass left after 5 half-lives should be:
100%*(1/2^5)= 100%/32=3..125%
helium
has the most neutrons in the nucleus
Explanation:
Sodium and potassium are in the same group on the periodic table because they both have similar number of valence electrons (1 electron) in their shells
Na = 2,8,1
K = 2,8,8,1
