Question

What is the equation for electron capture of uranium 237?

Answer 1

The equation is

`""_92^237"U" + _-1^0"e" →_91^237"Pa" + ν_e`

In electron capture, the nucleus pulls an outside electron into the nucleus. The electron combines with a proton to make a neutron and emits an electron neutrino.

Some texts omit the neutrino in the equation because it has no mass or charge. It serves only to carry away the excess energy.

`""_-1^1"H" + _-1^0"e" → _0^1"n" + ν_e`

Since proton becomes a neutron, the number of protons decreases by 1, but the atomic mass stays the same.

One example of electron capture involves uranium-237.

`""_92^237"U" + _-1^0"e" →_91^237"Pa" + ν_e`