How many protons are in the nuclues of an atom of beryllium?

Look at your periodic
Table. There are two numbers next to each element. Top number is mass number= protons+ neutrons

Atomic number= number if protons

Top number is mass number= protons+ neutrons  is my answer also

the catch is that the top numbers are atomic masses the bottom numbers are the numbers of protons and electrons in an uncharged atom. they are the number of that atoms as you would find them on the periodic table. further, the numbers on the left are used to determine the missing numbers on the right

so here we go

atomic mass

239 + 1 = y + 134 + 3 combine like terms

240 = y + 137             subtract 137 from both terms

240 - 137 = y

103 = y

atomic number

94 = z +54 + 0

94 = z + 54               subtract 54 from both sides.

40 = z

answer