Question

Strontium-87 (atomic number 38) decays to Rubidium-87 (atomic number 37). This is an example of ____________ decay. (1 point)
alpha
beta
gamma
electron capture

Answer 1

Looks like it has to be electron capture - a proton in the nucleus captures an electron from the atom's inner shell, forming a neutron and a neutrino. So 38 protons becomes 37, but the total number of protons+neutrons is still 87, as one proton converted into a neutron.

Answer 2

Although, beta-plus decay (positron emission - a proton is converted into a neutron, while releasing a positron and a neutrino) looks like it would give the same result - one less proton and one more neutron, same total number of protons and neutrons.

Answer 3

Actually Rubidium87 decays by beta- emission to Strontium-87 which is stable

Answer 4

I noticed that too, and thought it was odd that the question had it the wrong way around. I just assumed the teacher had done it that way on purpose or by accident.

Answer 5

It was electron capture, thanks.

Answer 6

@agent0smith I have the exact same question on my test but I don't have electron capture as one of my choices .

Answer 7

What options do you have?