What is the electron structure of a beryllium atom?

From the periodic table, beryllium has an atomic number 4. This means that beryllium has 4 electrons.

Now, the first energy level can hold only 2 electrons (which will occupy the s sublevel) wile the remaining two electrons will occupy the second energy level (also in the s sublevel).

Based on the above, the electronic configuration of beryllium will be as follows:
1s2 2s2