From 0a41137698e0641a7406cda843f1647ebf42f1ed Mon Sep 17 00:00:00 2001 From: eggy Date: Sat, 26 Sep 2020 16:24:12 -0400 Subject: [PATCH] chem: add spectrometer information --- docs/sch3uz.md | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) diff --git a/docs/sch3uz.md b/docs/sch3uz.md index 00beea1..2781456 100644 --- a/docs/sch3uz.md +++ b/docs/sch3uz.md @@ -77,9 +77,14 @@ Isotopes are atoms of the same element but with different masses, or alternative ### Atomic mass -The mass of every atom is represented relative to 1/12th of a carbon-12 atom. This mass is either unitless or expressed in terms of **atomic mass units (amu or u)**. On the periodic table, the **relative atomic mass** ($A_r$) is shown, which is a weighted average of each the mass of each natural isotope combined with their natural abundance (%occurence). +The mass of every atom is represented relative to 1/12th of a carbon-12 atom. This mass is either unitless or expressed in terms of **atomic mass units (amu or u)**. On the periodic table, the **relative atomic mass** ($A_r$) is shown, which is the sum of the masses of each isotope combined with their natural abundance (%abundance). -$$A_r = \text{%occurrence}×\text{mass number of isotope}$$ +$$A_r = \text{%abundance}×\text{mass number of isotope}$$ +$$m_a = \Sigma A_r$$ + +When calculating the atomic mass from the graph from a **mass spectrometer**, the sum of the natural abundances of each isotope may not equal 100 or 1 (not in %abundance). In this case, calculation of %abundance will need to be done before solving for $m_a$. + +A mass spectrometer may also provide mass in the form of $M/Z$, which represents mass over charge. For the sake of simplicity, $Z=1$, so $M/Z$ represents the mass of a particle. ### Atomic radius