Question

The charge of a beryllium-9 nucleus is
(1) +13 (3) +5
(2) +9 (4) +4

Answer 1

(4) +4 is your answer, since it is consisted of 4 protons and 5 neutrons.

Answer 2

Beryllium has an atomic number of 4, so a beryllium atom has 4 protons in its nucleus.

Since the charge of 1 proton is +1 and neutrons in the nucleus have 0 charge, the correct answer is (4) +4.

Hope this helps~