Question

When thorium (90 protons) ejects a beta particle, the resulting nucleus has

Question 18 options:

87 protons.

88 protons.

89 protons.

90 protons.

none of the above

Answer 1

none of the above

Step-by-step explanation:

The actual answer is '91 protons'. In fact, the beta decay of the thorium-234 is the following:

`{}_(90)Th \rightarrow {}_(-1)e+{}_(91)Pa`

where inside the nucleus of Thorium (90 protons), a neutron turns into an electron (the beta particle) + a proton. Therefore, the resulting nucleus (which is Protoactinium) has a total of 90+1 = 91 protons.

So, the correct answer would be '91 protons'.