Question about Atomic spectra I have basically 3 questions:-

*

*Why does atomic spectra (of any element) gives discrete lines

*What would it indicate if the lines were continuous

*Can the lines overlap? If not, why?

 A: To understand the first question you'd first need to know where the lines come from, first when electronic transitions occur in the atom the electrons move from one energy level to another, when the electron moves to a lower energy level, it releases surplus energy in the form of light. Depending on the energy level gap, the light emitted has a particular wavelength. Now getting to your questions, there aren't enough energy levels to create enough energy gaps to form a continuous spectra, i.e, the spectra only has lines with gaps in between.
A: All spectral lines have a finite width as they are broadened due to various mechanisms (see https://en.wikipedia.org/wiki/Spectral_line_shape ). If lines are close enough to each other, they can therefore overlap or even completely blend into each other. This is for instance the case near the series limit for atomic spectra (see https://en.wikipedia.org/wiki/Hydrogen_spectral_series )  
A: First, it was observed that elements emit EM radiation in quanta and these quanta have a precisely observable energy content. Using various techniques, these energy contents were separated and appear on a screen as sharp lines. Immediately, the question arose as to why excited electrons only emit radiation with certain energy contents and not with energy in between.
Nils Bor found a first answer. He proposed that electrons orbit around the nucleus and can only do so at certain distances from the centre. This was the beginning of wave mechanics. Although nothing orbits, we have inherited the orbitals with allowed electron distributions. When electrons are excited, they fall back to lower levels in discrete steps. The EM radiation emitted in the process are the lines we can observe on the screen. This is the answer to „Why does atomic spectra (of any element) gives discrete lines“.
If we not see any lines this means that to many elements (often as molecules and composites) are emitting EM radiation. The lines are detectable because to the left and to the right other lines exist from electrons from other elements. This is the answer to the question „What would it indicate if the lines were continuous.
And yes, the lines can overlap. You may have heard of the Pauli principle. It states that two (and only two) electrons in an atom can be identical except for the orientation of their magnetic dipoles. To follow the chronology of discoveries, first the splitting of spectral lines in magnetic fields had been observed and much later the Pauli principle was formulated. So without a magnetic field, two or more lines are one line on the screen. This answers your last question "Can the lines overlap?".
A: •A spectral line results when a photon of
specific energy (and thus frequency) is emitted. The emission occurs when the electron moves to an orbit closer to the nucleus as the atom’s energy changes from a higher state to a lower one.
Therefore, an atomic spectrum is not continuous because the atom’s energy is not continuous, but rather has only certain states.
•The occurrence of line spectra did not correlate with classical theory - that is, if an electron spiraled closer to the nucleus, the frequency of the radiation it emitted should be related to the time of revolution. That time changes smoothly on a spiral path, so the frequency of the radiation should change smoothly and, thus, create a continuous spectrum.
Rutherford’s model of a nuclear atom did not predict line spectra!
•The energy of an atom occurs in
discrete levels, and an atom changes energy by absorbing or emitting a photon of specific energy. Therefore, no two spectral lines ever intersect.
