Textbook Question
The series of emission lines of the hydrogen atom for which nf = 3 is called the Paschen series. (a) Determine the region of the electromagnetic spectrum in which the lines of the Paschen series are observed.
9. Quantum Mechanics
Emission Spectrum
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Consider the mass spectrum for a hypothetical element given below.
Which of the following statements correctly relates to this spectrum?
A
(A) The element has three stable isotopes.
B
(B) The isotope with a mass of 27 is the most abundant.
C
(C) The atomic mass of the element will be very close to 27.
D
(D) The most abundant isotope has a mass of 25.
E
Both (A) and (B) are correct.
F
All of the statements are correct.
Verified step by step guidance1
Examine the mass spectrum provided. The x-axis represents the mass of isotopes in atomic mass units (amu), and the y-axis represents the relative intensity or abundance of each isotope as a percentage.
Identify the peaks on the spectrum. There are three distinct peaks at masses 25, 26, and 27 amu, indicating the presence of three isotopes.
Assess the relative intensity of each peak. The peak at mass 27 amu has the highest intensity, suggesting it is the most abundant isotope.
Consider the statement options: (A) The element has three stable isotopes is correct because there are three peaks. (B) The isotope with a mass of 27 is the most abundant is correct based on the highest intensity peak.
Evaluate the atomic mass of the element. The atomic mass is a weighted average of the isotopes' masses based on their relative abundances. Since the isotope with mass 27 amu is the most abundant, the atomic mass will be closer to 27 amu.
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