
Nature of Matter
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the two previous equations, we can afrm that each xed shell, with principal
quantum number n and wavelength λ, corresponds to a xed energy value E.
Only an integer, and not a fraction, of wavelength can ensure stability to the revo-
lutionary motion of the electron around the nucleus, and only quantized values of
energy E will be possible, namely only discrete and not continuous values.
So, it is not possible for an electron to be at just any distance from the nucleus; it
can be at only well-dened distances. Also, the shells must necessarily be separated
and each shell is associated with a well-dened energy value. If an ...