Question

Please Help !
Radium -266 has a half-life of 1600 years. How long would it take for 1.0g of radium -266 to decay into 0.25g?
I don't understand how to work this out?

Answer 1

Whats half life? any idea?

Answer 2

first half life(after 1600 years) = 1/2 = .5 g left
after second half life (16oo+1600) means after 3200 years = .5/2 = .25 g left
So after 3200 years .25 g left .

Answer 3

thats right..after every half life ,,,the species becomes half of what it was

Answer 4

thanks @sarah786

Answer 5

yw :)