Question

which orbital is lower in energy in a many-electron atom?
○ 4s
○ 3s

Explanation:

In a many - electron atom, the energy of an orbital is related to the principal quantum number (n). The principal quantum number n represents the shell. For s - orbitals, as the value of n decreases, the energy of the orbital decreases. The principal quantum number for 3s is 3 and for 4s is 4. Since 3 < 4, the 3s orbital has lower energy than the 4s orbital.

Answer:

3s (the orbital with the option "3s")