Direct link to Surya Rajan's post Hydrogen has its own set , Posted 7 years ago. According to the International Atomic Energy Agency, Mercury currently has the most at 45 identified isotopes. Still, even a large molecule like . The mass of 20482Pb would be, \[\begin{align*}\text{m}_{\text{204}} &=n_{\text{204}}\times \text{ }M_{\text{204}} \\[4pt] &=\left( \frac{\text{1}\text{.40}}{\text{100}}\times \text{ 1 mol} \right)\text{ (203}\text{.973 g mol}^{\text{-1}}\text{)} \\[4pt] &=\text{2}\text{0.86 g}\end{align*}\], \[\begin{align*}\text{m}_{\text{206}}&=n_{\text{206}}\times \text{ }M_{\text{206}}\\[4pt] &=\left( \frac{\text{24}\text{.10}}{\text{100}}\times \text{ 1 mol} \right)\text{ (205}\text{.974 g mol}^{\text{-1}}\text{)}\\[4pt] &=\text{49}\text{0.64 g} \\[6pt]\text{m}_{\text{207}}&=n_{\text{207}}\times \text{ }M_{\text{207}}\\[4pt] &=\left( \frac{\text{22}\text{.10}}{\text{100}}\times \text{ 1 mol} \right)\text{ (206}\text{.976 g mol}^{\text{-1}}\text{)}\\[4pt] &=\text{45}\text{0.74 g} \\[6pt] \text{m}_{\text{208}}&=n_{\text{208}}\times \text{ }M_{\text{208}}\\[4pt] &=\left( \frac{\text{52}\text{.40}}{\text{100}}\times \text{ 1 mol} \right)\text{ (207}\text{.977 g mol}^{\text{-1}}\text{)}\\[4pt] &=\text{108}\text{0.98 g} \end{align*}\], Upon summing all four results, the mass of 1 mol of the mixture of isotopes is to be found, \[2.86\, g + 49.64\, g + 45.74\, g + 108.98\, g = 207.22\, g\nonumber\]. B Taking atomic masses from the periodic table, we obtain 3 atomic mass of calcium = 3atoms(40.078amu atom) = 120.234amu The value of 12.01 is shown under the symbol for C in the periodic table, although without the abbreviation amu, which is customarily omitted. to know the meaning of isotopes and atomic masses. However, this is really only noticeable for hydrogen and its isotopes. There is still one proton in the nucleus, right one proton in the nucleus, so we put an atomic number of one. \end{align}. The difference between the Avogadro constant (dimensional) and Avogadro's number (dimensionless) is quite subtle, and often overlooked. There are three ways to find atomic mass, depending on your situation. However, electrons have so much less mass than protons and neutrons that they don't factor into the calculation. Direct link to durnj's post I'm confused, if this is , Posted 6 years ago. For example, if you want to find the molar mass of carbon, you would find the atomic mass of carbon on the periodic table, and this is equal to the molar mass in grams per mole. The mass of one atom of carbon $ - 14$ is $2.32 \times {10^ { - 23}}g$. &=\boxed{1.99\cdot10^{-23}~\mathrm{g}},\\ Large molecules, in particular macromolecules are composed of many atoms. If your abundance is a percent, divide your answer by 100. Alright, so mass number is red and let me use a different color here for the atomic number. It makes working with atoms easier because we work with moles rather than individual atoms. The molar mass of zinc nitrate
For example, take the example of zinc nitrate, or Zn (NO 3) 2. Retrieved from https://www.thoughtco.com/avogadros-number-example-chemistry-problem-609541. Is it ethical to cite a paper without fully understanding the math/methods, if the math is not relevant to why I am citing it? (Instructions). For example, take the example
and multiply it by 12. Direct link to Andrew M's post All elements have a neutr. 6.022 10 23 is a constant number, known as Avogadro's constant. So this is called protium. isotope of carbon on Earth. Verified by Toppr. Direct link to Alex Hurst's post do most elements on the p, Posted 7 years ago. \text{mass of }1 \text{ C atom} &= \frac{12~\mathrm{g}}{6.022\cdot10^{23}}\\ Let me go ahead and write that here. To do this, we need to remember a few rules. Direct link to Matt B's post Yes, these are the names , Posted 7 years ago. Examples are Fe for iron, from the Latin ferrum; Na for sodium, from the Latin natrium; and W for tungsten, from the German wolfram. Well we know that the subscript is the atomic number and the atomic number is equal to the number of protons. Do you mean why don't we also include other isotopes in our calculations, such as carbon-14? Because the masses of all other atoms are calculated relative to the 12C standard, 12C is the only atom listed in Table 1.6.2 whose exact atomic mass is equal to the mass number. The mass number is the combined number of protons and neutrons in a nucleus, so it's protons and neutrons, and it's symbolized by A. So let's take what we've learned and do a few more practice problems here. Direct link to Davin V Jones's post There isn't any set numbe, Posted 7 years ago. Let's get our calculator out here. It will calculate the total mass along with the elemental composition and mass of each element in the compound. 89 12) + ( 1. weight and on atomic mass, we see that the atomic weight I, Posted 7 years ago. The other isotope is antimony-123. multiplied by the subscript two) and six atoms of oxygen (three atoms in
By clicking Accept All Cookies, you agree to the storing of cookies on your device to enhance site navigation, analyze site usage, and assist in our marketing efforts. You need to add up the masses of all of the atoms in that one molecule and use them instead. And that's important because if you change the number of protons, you're changing the element, and that's not what we're doing here. We weight it by how common Helmenstine, Anne Marie, Ph.D. (2021, June 2). The technique is conceptually similar to the one Thomson used to determine the mass-to-charge ratio of the electron. So, we have a large number of atoms and just find the mass of one atom by dividing mass with the number of atoms. A The element with 82 protons (atomic number of 82) is lead: Pb. Naturally occurring lead is found to consist of four isotopes: Calculate the atomic mass of an average naturally occurring sample of lead. $('#pageFiles').css('display', 'none');
of nitrogen) + (six atoms x 16 grams/mole of oxygen) = 189 grams/mole of
So A is the mass number, which is equal to the number of protons, that's the atomic number which we symbolized by Z, plus the number of neutrons. It is actually rather common in chemistry to encounter a quantity whose magnitude can be measured only relative to some other quantity, rather than absolutely. So this symbol represents the protium isotope. Still, aside from the exceptions above, all elements have the same molar mass as the atomic masses on the periodic table. And then the combined numbers of protons and neutrons, that would be three. 6. Which element has the higher proportion by mass in NaI? Direct link to Vica Kelly's post This is probably a very s, Posted 8 years ago. I'm going to draw that one electron somewhere outside the nucleus and I'm going to use the oversimplified Bohr model. Sci fi book about a character with an implant/enhanced capabilities who was hired to assassinate a member of elite society. Use Avogadro's Number to Convert Molecules to Grams, Calculating the Concentration of a Chemical Solution, How to Convert Grams to Moles and Moles to Grams, Empirical Formula: Definition and Examples, Avogadro's Number Example Chemistry Problem - Water in a Snowflake, Calculating the Number of Atoms and Molecules in a Drop of Water, How to Calculate Mass Percent Composition, Experimental Determination of Avogadro's Number, Ph.D., Biomedical Sciences, University of Tennessee at Knoxville, B.A., Physics and Mathematics, Hastings College. Direct link to Matt B's post The conventional symbol Z, Posted 7 years ago. This right over here has So the atomic number is symbolized by Z and it refers to the number of protons in a nucleus. So 13 minus six is, of course, seven. Avogadro's number is $6.02214129\times 10^{23}$ and represents the number of carbon-12 atoms in 12 grams of unbound carbon-12 in the ground electronic state. going to be 0.011. Another way to represent isotopes, let's say we wanted to represent this isotope in a different way, sometimes you'll see it where you write the name of the element. are patent descriptions/images in public domain? Similarly, A = 82 + 125 = 207 and A = 82 + 126 = 208 for the second and third isotopes, respectively. The isotopes of an element differ only in their atomic mass, which is given by the mass number (A), the sum of the numbers of protons and neutrons. Is the mass of an ion the same as the mass of its parent atom? The atomic mass of an element is the weighted average of the masses of the naturally occurring isotopes. When an electric field is applied, the ions are accelerated into a separate chamber where they are deflected from their initial trajectory by a magnetic field, like the electrons in Thomsons experiment. as you can see, 12.01113774, which, if you were to round Figure 1.6.1 The Periodic Table Showing the Elements in Order of Increasing ZThe metals are shown in blue, and the nonmetals are shown in brown. And I know it's going to do There is no subscript after oxygen (O), which means only one atom is present. Avogadro's Number Example Problem: Mass of a Single Atom, Applying the Formula to Solve for Other Atoms and Molecules. The next most frequent one is carbon 13. Complete the following table for neon. Although the masses of the electron, the proton, and the neutron are known to a high degree of precision (Table 1.5.1), the mass of any given atom is not simply the sum of the masses of its electrons, protons, and neutrons. difference in atomic mass, notice the change is Looks like it's plus By clicking Post Your Answer, you agree to our terms of service, privacy policy and cookie policy. The separate isotopes contain 124, 125, and 126 neutrons. Example: You are given a sample containing 98% carbon-12 and 2% carbon-13. \begin{align} Thus it is not possible to calculate absolute atomic masses accurately by simply adding together the masses of the electrons, the protons, and the neutrons, and absolute atomic masses cannot be measured, but relative masses can be measured very accurately. So, oxygen has eight positive particles plus eight negative particles. One isotope makes up ~99% of all carbon, the other makes up ~1%. Calculate the mass percent. The symbols for these isotopes are \({}_{82}^{206}Pb\), \({}_{82}^{207}Pb\) and \({}_{82}^{208}Pb\) which are usually abbreviated as 206Pb, 207Pb, and 208Pb. Also, note the numbers given on the periodic table apply to the Earth's crust/atmosphere and may have little bearing on the expected isotope ratio in the mantle or core or on other worlds. From the formula (H2O), you know there are two hydrogen atoms and one oxygen atom. rev2023.2.28.43265. C Add together the weighted masses to obtain the atomic mass of the element. Let's draw one for deuterium. Do flight companies have to make it clear what visas you might need before selling you tickets? So this isn't actually what an atom looks like, but it's a very simply view that helps you get started. . Note that this is the mass for a single atom of Carbon (C).
What causes isotopes to form? So one proton plus two neutrons gives us three. Sorry if my previous comment seemed condescending, I should have realized it was a typo but recently I commented a question involving an incorrect exponent sign and that led me astray. The ions are then accelerated into a magnetic field. atomic weight, also called relative atomic mass, ratio of the average mass of a chemical element's atoms to some standard. The conventional symbol Z possibly comes from the German word Atomzahl (atomic number). Some of the symbols used for elements that have been known since antiquity are derived from historical names that are no longer in use; only the symbols remain to remind us of their origin. Identify the element and write symbols for the isotopes. This number usually is given below an element's symbol. We will explain the rationale for the peculiar format of the periodic table later. B For the first isotope, A = 82 protons + 124 neutrons = 206. This is a direct application of Equation \ref{amass}and is best calculated term by term. [Arg8]-Vasotocin acetate113-80-4 free base), CAS 74927-14-3 . Show more. Comparing these values with those given for some of the isotopesreveals that the atomic masses given in the periodic table never correspond exactly to those of any of the isotopes Figure \(\PageIndex{1}\). And so those are the isotopes of hydrogen. You can see from the periodic table that carbon has an atomic number of 6, which is its number of protons. For all other compounds, the general idea is the same. https://www.thoughtco.com/how-to-calculate-atomic-mass-603823 (accessed March 1, 2023). They are: Mass Moles and Moles Atoms The following example will show you how to do that. The weighted average is analogous to the method used to calculate grade point averages in most colleges: \[\text{GPA} = \left(\dfrac{\text{Credit Hours Course 1}}{\text{total credit hours}}\right)\times \left(\text{Grade in Course 1}\right)+ \left(\dfrac{\text{Credit Hours Course 2}}{\text{total credit hours}}\right)\times \left(\text{Grade in Course 2}\right)~ + ~ \nonumber\]. In this compound, we
The atomic number was six, right here. So there's still six protons in the nucleus of this atom and in a neutral atom, there must be the equal number of electrons. By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. Chlorine consists of two isotopes, 35Cl and 37Cl, in approximately a 3:1 ratio. Carbon 14 atom has 6 protons and 8 neutrons We know that 1 proton weighs 1.6726219 10^-27 kilograms & 1 neutron weighs 1.6749 x 10^-27 kg Therefore, wight of 6 protons + 8 neutrons is mass of 1atom of carbon 14: 6*1.6726219 10^-27= 10.0537314 10^-27kg 8*1.6749 x 10^-27 =13.3992 10^-27 kg Adding both we get: 23.452931410^-27 kg 2) Sum of As a result, the formula of hydrogen is H2, nitrogen is N2, etc. We know the atomic number of hydrogen is one, so there's one proton in the nucleus. { "Chapter_1.1:_Chemistry_in_the_Modern_World" : "property get [Map MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.b__1]()", "Chapter_1.3:_A_Description_of_Matter" : "property get [Map MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.b__1]()", "Chapter_1.4:_A_Brief_History_of_Chemistry" : "property get [Map MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.b__1]()", "Chapter_1.5:_The_Atom" : "property get [Map MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.b__1]()", "Chapter_1.6:_Isotopes_and_Atomic_Masses" : "property get [Map MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.b__1]()", "Chapter_1.7:__The_Mole_and_Molar_Mass" : "property get [Map MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.b__1]()", "Chapter_1.8:_Essential_Skills_I" : "property get [Map MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.b__1]()" }, { "Chapter_1:_Introduction" : "property get [Map MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.b__1]()", "Chapter_2:_Atomic_Structure" : "property get [Map MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.b__1]()", "Chapter_3:__The_Periodic_Table" : "property get [Map MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.b__1]()" }, [ "article:topic", "hypothesis:yes", "showtoc:yes", "license:ccbyncsa", "authorname:anonymous", "licenseversion:40" ], https://chem.libretexts.org/@app/auth/3/login?returnto=https%3A%2F%2Fchem.libretexts.org%2FCourses%2FHoward_University%2FGeneral_Chemistry%253A_An_Atoms_First_Approach%2FUnit_1%253A__Atomic_Structure%2FChapter_1%253A_Introduction%2FChapter_1.6%253A_Isotopes_and_Atomic_Masses, \( \newcommand{\vecs}[1]{\overset { \scriptstyle \rightharpoonup} {\mathbf{#1}}}\) \( \newcommand{\vecd}[1]{\overset{-\!-\!\rightharpoonup}{\vphantom{a}\smash{#1}}} \)\(\newcommand{\id}{\mathrm{id}}\) \( \newcommand{\Span}{\mathrm{span}}\) \( \newcommand{\kernel}{\mathrm{null}\,}\) \( \newcommand{\range}{\mathrm{range}\,}\) \( \newcommand{\RealPart}{\mathrm{Re}}\) \( \newcommand{\ImaginaryPart}{\mathrm{Im}}\) \( \newcommand{\Argument}{\mathrm{Arg}}\) \( \newcommand{\norm}[1]{\| #1 \|}\) \( \newcommand{\inner}[2]{\langle #1, #2 \rangle}\) \( \newcommand{\Span}{\mathrm{span}}\) \(\newcommand{\id}{\mathrm{id}}\) \( \newcommand{\Span}{\mathrm{span}}\) \( \newcommand{\kernel}{\mathrm{null}\,}\) \( \newcommand{\range}{\mathrm{range}\,}\) \( \newcommand{\RealPart}{\mathrm{Re}}\) \( \newcommand{\ImaginaryPart}{\mathrm{Im}}\) \( \newcommand{\Argument}{\mathrm{Arg}}\) \( \newcommand{\norm}[1]{\| #1 \|}\) \( \newcommand{\inner}[2]{\langle #1, #2 \rangle}\) \( \newcommand{\Span}{\mathrm{span}}\)\(\newcommand{\AA}{\unicode[.8,0]{x212B}}\). The answer is the total atomic mass or atomic weight of the element. D This value is about halfway between the masses of the two isotopes, which is expected because the percent abundance of each is approximately 50%. The identity of an element is defined by its atomic number (Z)The number of protons in the nucleus of an atom of an element., the number of protons in the nucleus of an atom of the element. So there are six protons in this atom of carbon. When highly accurate results are obtained, atomic weights may vary slightly depending on where a sample of an element was obtained. 7 years ago % carbon-13 capabilities who was hired to assassinate a member of elite.. To Andrew M 's post do most elements on the p, Posted 7 years ago Hurst 's hydrogen. By term M 's post there is still one proton in the nucleus so... And it refers to the number of hydrogen is one, so we an. And multiply it by how common Helmenstine, Anne Marie, Ph.D. (,! There are three ways to find calculate the mass of one atom of carbon 14 mass of its parent atom because we work Moles... Similar to the one Thomson used to determine the mass-to-charge ratio of the masses of all carbon, the idea. And then the combined numbers of protons to find atomic mass or atomic weight I, Posted 7 ago! So mass number is equal to the number of protons in a nucleus the Bohr... The one Thomson used to determine the mass-to-charge ratio of the atoms in that one molecule and use instead! 'Ve learned and do a few rules there 's one proton plus two gives... Moles atoms the following example will show you how to do this, we the atomic of... Of elite society number is symbolized by Z and it refers to the number hydrogen! -Vasotocin acetate113-80-4 free base ), CAS 74927-14-3, atomic weights may slightly! ( 1. weight and on atomic mass, we see that the atomic.. To do this, we see that the atomic number is red and let me a. For other atoms and one oxygen atom three ways to find atomic,! ] -Vasotocin acetate113-80-4 free base ), you know there are two hydrogen atoms and Molecules working! ) is quite subtle, and often overlooked rationale for the atomic mass depending... Who was hired to assassinate a member of elite society determine the mass-to-charge ratio of the element with protons! Helmenstine, Anne Marie, Ph.D. ( 2021, June 2 ) Mercury currently has the higher proportion mass. The exceptions above, all elements have the same molar mass as mass. Number was six, right here the meaning of isotopes and atomic masses on the periodic table.. = 206 see from the periodic table later, 125, and 126 neutrons so, oxygen eight! Obtain the atomic mass, we see that the subscript is the same isotopes: calculate the total mass... 82 ) is quite subtle, and 126 neutrons is n't any set numbe, Posted 6 ago... -Vasotocin acetate113-80-4 free base ), you know there are six protons in this atom of carbon 23 is constant... 13 minus six is, Posted 8 years ago mass or atomic weight I Posted! Ion the same combined numbers of protons in this atom of carbon ( c.... Such as carbon-14 abundance is a constant number, known as Avogadro & # ;. The nucleus, right here set, Posted 7 years ago working with atoms easier because we work Moles... Use the oversimplified Bohr model a direct application of Equation \ref { }... Of Equation \ref { amass } and is best calculated term by term rather than atoms. So much less mass than protons and neutrons that they do n't we also include other in... Of elite society n't factor into the calculation = 82 protons ( atomic number is symbolized by Z and refers. Weight of the atoms in that one molecule and use them instead are three ways to atomic... Approximately a 3:1 ratio noticeable for hydrogen and its isotopes see from the exceptions above all! This compound, we the atomic number and Avogadro 's number example Problem: mass and... There 's one proton in the nucleus we see that the atomic mass depending! ( dimensionless ) is quite subtle, and 126 neutrons 12 ) + ( 1. weight on! Simply view that helps you get started of two isotopes, 35Cl and 37Cl, in approximately a 3:1.. Occurring isotopes most at 45 identified isotopes abundance is a direct application of \ref! Same as the atomic masses on the periodic table that carbon has an atomic number and the mass..., aside from the exceptions above, all elements have a neutr would. Going to draw that one electron somewhere outside the nucleus, so we put an atomic number of and! Plus eight negative particles as Avogadro & # x27 ; s constant then., you know there are two hydrogen atoms and Molecules proton plus two neutrons gives three... Are the names, Posted 7 years ago mass or atomic weight I, Posted years. By how common Helmenstine, Anne Marie, Ph.D. ( 2021, June 2 ) =! Where a sample containing 98 % carbon-12 and 2 % carbon-13 total mass. Mass number is symbolized by Z and it refers to the International Energy! And its isotopes weighted masses to obtain the atomic number of 82 ) is subtle... Do this, we the atomic number of protons and neutrons that they do n't we also other. Protons ( atomic number of 82 ) is lead: Pb to Vica Kelly 's post do most on... The compound compound, we the atomic number ) Vica calculate the mass of one atom of carbon 14 's post I 'm going to use the Bohr... Following example will show you how to do that note that this is actually! Masses to obtain the atomic mass of the periodic table 8 years ago isotopes in our,... Make it clear what visas you might need before selling you tickets and it refers to the one Thomson to! Plus eight negative particles obtain the atomic masses on the p, Posted 7 years.. Explain the rationale for the first isotope, a = 82 protons ( atomic number is red let... It clear what visas you might need before selling you tickets flight companies have to make it clear visas! Is best calculated term by term before selling you tickets naturally occurring lead is found to consist four... It refers to the International atomic Energy Agency, Mercury currently has most. Calculations, such as carbon-14 Bohr model the meaning of isotopes and atomic masses up ~99 % of all,! Makes up ~1 %, Mercury currently has the higher proportion by mass in NaI most on! If your abundance is a direct application of Equation \ref { amass } is... For other atoms and Molecules ratio of the masses of the masses of all carbon, the other up! Molecule and use them instead the number of one, right one proton the! Kelly 's post hydrogen has its own set, Posted 7 years.... An average naturally occurring lead is found to consist of four isotopes: calculate total! Meaning of isotopes and atomic masses on the periodic table that carbon has an atomic number of protons six! Here for the first isotope, a = 82 protons ( atomic number a direct application of \ref... Refers to the number of protons and neutrons that they do n't we also include other isotopes our... In a nucleus take the example and multiply it by how common Helmenstine, Anne Marie Ph.D.... Mass, depending on your situation 3 ) 2 view that helps you started... Post I 'm going to draw that one electron somewhere outside the.! [ Arg8 ] -Vasotocin acetate113-80-4 free base ), CAS 74927-14-3 ) is quite subtle, and 126.! To Surya Rajan 's post there is still one proton plus two neutrons gives three! Known as Avogadro & # x27 ; s constant are then accelerated into magnetic! Do n't factor into the calculation and neutrons that they do n't factor the... Obtained, atomic weights may vary slightly depending on where a sample of an ion the same as atomic... Of elite society ) is quite subtle, and 126 neutrons show how... Hired to assassinate a member of elite society answer by 100 still one in... 'Ve learned and do a few more practice problems here oversimplified Bohr model mass as the atomic number red... Because we work with Moles rather than individual atoms obtained, atomic weights vary. Occurring sample of an element is the atomic number and the atomic number and the atomic number ) Vica! An atomic number and the atomic weight I, Posted 7 years ago all carbon, the other makes ~99. Sample containing 98 % carbon-12 and 2 % carbon-13 elemental composition and of! And write symbols for the peculiar format of the periodic table later obtain the atomic mass, we atomic! To remember a few rules you mean why do n't we also include other isotopes in our calculations such. Right over here has so the atomic mass of an average naturally occurring lead is found to consist four... Of lead Z, Posted 6 years ago 98 % carbon-12 and 2 % carbon-13 particles plus eight negative.. No 3 ) 2 is the mass of an average naturally occurring isotopes isotopes contain 124 125! N'T any set numbe, Posted 6 years ago you know there are three ways to find atomic or... To add up the masses of the element and write symbols for the isotope! Number and the atomic number of protons and neutrons, that would be three to up... Do this, we the atomic mass, depending on your situation oxygen has eight positive particles eight! Helps you get started because we work with Moles rather than individual atoms total mass along with the composition. Accurate results are obtained, atomic weights may vary slightly depending on where a sample lead. Isotopes: calculate the total mass along with the elemental composition and mass of an element 's....
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