what happens when Barium 139 decays by electron capture?

Question

I have Cesium as a result but what else belongs in the equation.

Answer 1

in electron capture the atomic number of the produat increases by 1 and there is no change in the atomic weight
hence
as there is electron capture on BARIUM139(atomic number=56) so as a product we get LANTHANUM 139 (with atomic number =57)
BALANCED EQUATION
BARIUM139 + electron ------------->LANTHANUM139

Answer 2

when a nucleus emits an electron its mass is unchanged but its atomic number increses one since in the nucleus 1 neuton is transformed in 1 proton.

Result the atomic number Z increases one unit
For Cesium Z = 55 .
You obtain Bariumm Z=56