1s orbitals is the orbitals in which electrons have the lowest energy since it is close in the nucleus of an atom.
The energy level closes to the nucleus of an atom have the least energy while the last energy level have the highest energy since it is far from the nucleus of an atom. 1s orbitals is the closest and can hold only 2 electrons.
For more information kindly visit the link provided below:
Bake it at 350°F (175°C) for 50 minutes, until golden brown. Remove the pie from the oven, let it cool for a hot minute and then remove the tin foil and weights. Put the pie back into the oven for 10 minutes. Bake all pies in a rack fitted to the middle of your oven and at 350°F (175°C), always.