Which of the following acts like fingerprints that identify atoms and molecules?

• A. Their melting points
• B. Their atomic mass
• C. Their unique atomic spectra
• D. Their electron configuration

Answer: (C)

Verified step by step guidance

1. Understand that atoms and molecules can be identified by unique characteristics that serve as their 'fingerprints'.
2. Recognize that melting points and atomic mass are physical properties but are not unique enough to serve as definitive identifiers for all atoms or molecules.
3. Recall that electron configuration describes the arrangement of electrons but can be similar for different atoms or ions in certain cases.
4. Focus on atomic spectra, which arise from electrons transitioning between energy levels, emitting or absorbing light at specific wavelengths unique to each element.
5. Conclude that the unique atomic spectra act like fingerprints because each element has a distinct set of spectral lines that can be used to identify it precisely.