Beta decay:
Beta decay occurs when a neutron is unstable. nucleus converted into a proton and an electron and the nuclear electron ejected from the nucleus:
₀n¹ → ₁P¹ + ₋₁β⁰
₅₅Cs¹³⁷ → ₅₆Ba¹³⁷ + ₋₁β⁰
I thank that your answer is C.
You could use percent error. Absolute | | of accepted value minus experimental value \ divided by accepted value multiply by 100 and that is your answer
Transition metals are metals found in the middle of the periodic table. The answer is Pb.