Radioactive Decay: Isotope A to B in 1 Hour

[Bachelier]

If isotope A decays to isotope B.
Does it mean that if within 1 hour we have 10 mg of A that decays, do we get exactly 10 mg of B after one hour?

thanks

 

[ideasrule]

That depends. In alpha decay, isotope A would decay to isotope B plus a helium nucleus, which escapes, so isotope B would weigh slightly less. In beta and gamma decay, the mass change is insignificant.

 

[Bachelier]

This is Beta decay.

so I guess 10 mg of A will give me approx. 10 mg of B.