Elemental chlorine exists as a diatomic molecule Cl2.

Chlorine atoms exist in two different isotopes 35Cl and 37Cl.

In the mass spectrum of chlorine molecules,
how may peaks due to chlorine atoms would be observed? 2

how many different peaks due to the molecular ion would be observed? 3

35Cl is three times as abundant as 37Cl.
Which of the three molecular ion peaks would be least intense?
m/z 74
m/z 72
m/z 70

I found this site that does a really neat job of explaining the five lines ones gets from Cl2. Scroll down from the top until you get to the Cl2 part.

http://www.chemguide.co.uk/analysis/masspec/elements.html

In the mass spectrum of chlorine molecules, there would be two peaks due to chlorine atoms, representing the two different isotopes (35Cl and 37Cl).

There would be three different peaks due to the molecular ion in the mass spectrum. These peaks would correspond to the different combinations of isotopes in the Cl2 molecule.

Since 35Cl is three times as abundant as 37Cl, the peak with m/z 72 would be the least intense. This is because the molecular ion with two 35Cl atoms (35Cl2) would be the most abundant and contribute the most to the overall intensity of the peaks. The molecular ion with one 35Cl and one 37Cl atom (35Cl37Cl) would be less intense, and the molecular ion with two 37Cl atoms (37Cl2) would be the least abundant and therefore have the least intensity among the three peaks.

To understand the answers to these questions, it is helpful to learn about the concept of isotopes, mass spectrometry, and the molecular ion peaks.

Isotopes:
Isotopes are atoms of the same element that have different numbers of neutrons in their nuclei, resulting in different masses. Chlorine atoms exist in two isotopes: 35Cl and 37Cl. The number refers to the sum of the protons and neutrons in the nucleus.

Mass Spectrometry:
Mass spectrometry is a technique used to determine the molecular composition and mass of a compound. It involves the ionization of molecules, followed by their separation based on their mass-to-charge ratio (m/z) using magnetic or electric fields. The resulting data can be represented as a mass spectrum, which shows the intensity of ions at different m/z values.

Peaks for Chlorine Atoms:
Since elemental chlorine exists as a diatomic molecule (Cl2), when it undergoes ionization in a mass spectrometer, it breaks down into individual chlorine atoms. Each chlorine atom will have the same mass, either 35 or 37, depending on the isotope. Therefore, there will be two peaks observed in the mass spectrum due to chlorine atoms.

Peaks for Molecular Ions:
The molecular ion peak in a mass spectrum represents the intact molecule without any fragmentation. In the case of chlorine molecules (Cl2), there are three possible molecular ions based on their isotopic composition:

- One molecular ion will contain two 35Cl atoms (m/z 70).
- Two molecular ions will contain one 35Cl and one 37Cl atom (m/z 72).
- One molecular ion will contain two 37Cl atoms (m/z 74).

Relative Abundance:
The question states that 35Cl is three times as abundant as 37Cl. This means that in a sample of chlorine molecules, the ratio of 35Cl to 37Cl atoms will be 3:1.

Least Intense Molecular Ion Peak:
Since 35Cl is more abundant, the molecular ion containing two 37Cl atoms (m/z 74) will be the least intense. This is because there will be fewer molecules with this isotopic composition compared to the other two molecular ion peaks.

To summarize:
- There will be two peaks observed due to chlorine atoms (35Cl and 37Cl).
- There will be three different peaks observed due to the molecular ions of chlorine molecules (m/z 70, m/z 72, and m/z 74).
- The molecular ion peak with m/z 74 will be the least intense.

Please explain each of the question....I guessed which is not good..I need to understand.........