Which modification to the atomic model addressed the issue of electron stability that was present in Rutherford's model?

• A. Electrons are embedded within a positively charged sphere
• B. Electrons move randomly around the nucleus without any defined path
• C. Atoms consist of indivisible particles with no internal structure
• D. Electrons occupy quantized energy levels as proposed by Niels Bohr

Answer: (D)

Verified step by step guidance

1. Recall that Rutherford's atomic model described the atom as having a small, dense, positively charged nucleus with electrons orbiting around it, but it could not explain why electrons do not spiral into the nucleus due to electromagnetic radiation loss.
2. Understand that the problem of electron stability arises because, according to classical physics, accelerating charged particles (like electrons in orbit) should emit radiation and lose energy, causing them to collapse into the nucleus.
3. Recognize that Niels Bohr introduced the concept of quantized energy levels, where electrons can only occupy certain allowed orbits with fixed energies, preventing the continuous loss of energy and collapse.
4. Bohr's model proposed that electrons do not radiate energy while in these stable, quantized orbits, thus addressing the stability issue present in Rutherford's model.
5. Therefore, the key modification was the introduction of quantized electron energy levels, which explained electron stability and the discrete spectral lines observed in hydrogen.