You will compare the 3s orbital and the 3p orbital. It may be helpful to consider the radial probability plots using the image below. The electrons residing in the 3s orbital are, on average, closer to the nucleus of the atom. Fill in the blanks with 3p or 3s. The electrons residing in the orbital are, on average, closer to the nucleus of the atom. The electrons residing in the orbital penetrate most. The electrons residing in the orbital are likely to experience the stronger Zeff.