Who proposed that the orbits of electrons in an atom are elliptical?

Option 3 : Sommerfeld

Explanation:

• Bohr's atomic theory failed to explain the hydrogen spectra and spectrum of multi-electron systems.
• According to Bohr, the circular orbits of the electrons are planar, however, this is not true and the electrons move around the nucleus in three-dimensional space.
• It fails to follow Heisenberg's Uncertainty principle.
• In order to explain the fine lines in the hydrogen spectrum, Sommerfeld proposed elliptical orbits instead of circular orbits.
• On this basis, a new quantum number called the azimuthal quantum number in addition to the principal quantum number (n).
• So, the correct option is Sommerfeld.

• According to Sommerfeld, an electron revolving around a centrally positively charged nucleus is so influenced by the charges that it is set into motion in elliptical orbits.
• The nucleus is situated at one of the foci.
• An ellipse contains a major and a minor axis of different lengths.

[ alt="F1 Pooja.J 30-01-21 Savita D1" on sommerfeld elliptical model andhra pradesh board class chemistry src="//storage.googleapis.com/tb-img/production/21/01/F1_Pooja.J_30-01-21_Savita_D1.png" style="height: 173px; width: 347px;">