Question

${}_{4}B{e}^7$ captures a $K$ electron into its nucleus. What is the mass number and atomic number of the nuclide formed?

• A. 3,7
• B. 4,8
• C. 3,8
• D. 4,7

Answer 1

Answer: (A)

${}_{4}B{e}^7+{}_{-1}{e}^0\to {}_{3}L{i}^7$
So, atomic number $=3$, mass number $=7$