The radial probability distribution curve obtained for an orbital wave function has 3 peaks and 2 radial nodes. The valence electron of which one of the following metals does this wave function correspond to ?

• Since the radial probability distribution curve has 3 peaks, it means that for it n=3 and l=0.
•  Moreover, it has two radial nodes ie, n−$\mathcal{l}$−1=2, which also satisfied the previous condition, ie, 3−0−1=2. 
• Hence, the valence electron of the metal must present in 3s−orbital

Element                   Configuration             

Cu₂₉​                            1s²2s²2p⁶3s²3p⁶3d¹⁰4s¹

Li₃​                                1s²2s¹

K_19​                              1s²2s²2p⁶3s²3p⁶

Na_11​                            1s²2s²2p⁶3s¹

∵Only the valence electron of Na_11​ is in 3s orbital