Which type of spectrum was analyzed to determine the atomic numbers of elements?

• A. X-ray emission spectrum
• B. Continuous spectrum
• C. Visible light emission spectrum
• D. Infrared absorption spectrum

Answer: (A)

Verified step by step guidance

1. Understand that the question asks about the type of spectrum used to determine atomic numbers of elements, which relates to identifying elements based on their unique spectral lines.
2. Recall that atomic numbers correspond to the number of protons in an element's nucleus, and that certain spectra reveal information about the electronic structure and nuclear charge.
3. Recognize that the X-ray emission spectrum arises when inner-shell electrons are ejected and electrons from higher energy levels fall into these vacancies, emitting X-rays characteristic of the element's atomic number.
4. Contrast this with other spectra: continuous spectra show a full range of wavelengths without discrete lines, visible light emission spectra relate to outer electron transitions but do not directly determine atomic number, and infrared absorption spectra involve molecular vibrations rather than atomic structure.
5. Conclude that the X-ray emission spectrum is the correct type of spectrum used to determine atomic numbers because its characteristic lines are directly related to the nuclear charge and electron transitions in inner shells.