Determining # of Beta Decays from Alpha Decay

[Kim_Jong]

Homework Statement

Consider a nuclear process in which U-238 undergoes several Alpha and Beta decays and becomes Pb-206. How many Alpha and Beta decays occur in this process?

Relevant Equations

.

Alpha particle has two protons and neutrons so mass = 4.

4x = 238 -206.

x = 1/4(238-206) = 8 Alpha decays.

How would I determine the number of Beta decays? Since the mass doesn't change here.

 

[etotheipi]

How many protons are left if you do all the alpha decays first?

 

[Kim_Jong]

76. So there will be 6 Beta decays.