Chemistry

The key is understanding that a higher nuclear charge pulls electrons closer and binds them more tightly. When an electron transitions between energy levels, the energy gap $\Delta E$ grows larger with increasing atomic number $Z$ — because both the initial and final energy levels become more negative (deeper). Since $E = h c / \lambda$, a larger energy gap means shorter wavelength. Think of it as a stronger "pull" from the nucleus creating a bigger energy difference to bridge.

The key is understanding that a higher nuclear charge pulls electrons closer and binds them more tightly. When an electron transitions between energy levels, the energy gap $\Delta E$ grows larger with increasing atomic number $Z$ — because both the initial and final energy levels become more negative (deeper). Since $E = h c / \lambda$, a larger energy gap means shorter wavelength. Think of it as a stronger "pull" from the nucleus creating a bigger energy difference to bridge.