Which of the following are correct? electrons generally occupy the lowest energy orbital first. the c atom has two unpaired electrons. the he atom has two electrons that have parallel spin in its 1s orbital. the arrangement of the orbitals is the same in a multielectron atom and a single-electron atom. in the li atom, the 3s, 3p, and 3d orbitals have different energies. the he atom has one electron each in 1s and 2s orbitals.