To determine how many protons are in the nucleus of an atom of beryllium (Be), we need to refer to the periodic table of elements. Every element on the periodic table has an atomic number, which represents the number of protons in the nucleus of an atom of that element.
1. Locate beryllium (Be) on the periodic table.
2. Identify the atomic number of beryllium.
3. The atomic number of beryllium is 4.
4. Therefore, beryllium has 4 protons in its nucleus.
So, the correct answer is:
D) 4
