An atom (or aggregation of atoms) of a particular element identified by mass number and distinguished by the number of neutrons in its nucleus.

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Relative abundances of isotopes from weighted average mass [on hold]

In nature, nitrogen consists of two stable isotope, N-14 with a mass of 14.00 amu and N-15 with a mass of 15.00 amu. The average atomic mass of nitrogen is 14.01 amu. What does the average atomic was ...
19
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3answers
2k views

Why are isotopes of hydrogen the only ones with special names?

Why does no other element but hydrogen get special names for its isotopes?
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1answer
873 views

Why atomic masses aren't integers?

Most of the elements have isotopes, so the atomic masses are calculated depending on the percentage of the existing isotopes. That is clear. However, what about elements that have only one isotope ...
3
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1answer
73 views

Correct Electron Configuration of Ni-28

I have seen two electron configurations for $\ce{_{28}Ni}$ in my chemistry textbook: $$[\ce{Ar}]~3d^8~4s^2$$ $$[\ce{Ar}]~3d^9~4s^1$$ Which of those is ACTUALLY the correct one (in real life, reality)? ...
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20 views

Do we have a reasonable assurance that relative atomic mass is constant throughout the universe? [duplicate]

I know atomic mass can be (over) simplified as the average mass of all isotopes of a given element weighted by the ratio of their natural occurrence. I also know that, as far as we know, refining ...
15
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2answers
431 views

Is the relative natural abundance of isotopes of an element the same everywhere?

Wherever you find potassium, the isotopes are present in a set percentage that exists the same everywhere in nature, but why is that? Does it have something to do with how the element is produced?
4
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1answer
43 views

Dispersion of Lithium Ions in Nature (Ratio Similar to Isotopes?)

I'm working on a project that identifies average characteristics of different elements. I'm stuck on lithium, I can't find a way to ratio lithium I and lithium II that symbolizes how it is in nature. ...
22
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1answer
2k views

How come uranium's relative atomic mass is 238.03 when it only contains isotopes with a mass number of 238 or less?

I have always been led to understand that the mass of an element on the periodic table is the weighted average atomic mass over all naturally occurring isotopes. This seems to make sense with all the ...
11
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2answers
253 views

Radical formation via tritium to helium decay

Following on from this question about tritium water, I was wondering whether the decay of tritium to helium-3 has ever been used in organic synthesis. Such a transition would presumably result in no ...
17
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1answer
864 views

Are there any known chemical properties of tritium water that make it unusually different from protium water?

I suppose the first question supporting the main question is, has tritium water ever been synthesized in sufficient quantity to test chemical properties? If so, and apart from the obvious radioactive ...
1
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1answer
70 views

What number should go underneath this fictitious element on the periodic table? [closed]

A new element (Wickium) was discovered on Mars. The isotopes of Wickium are Wickium-199, Wickium-200, and Wickium 201. The percent abundance of Wickium's isotopes are as follows: $$\ce{^199Wi} = ...
12
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2answers
503 views

For a given element do heavier isotopes form stronger bonds than lighter isotopes?

I know that $\ce{C-D}$ and $\ce{C-T}$ bonds are stronger than $\ce{C-H}$ bonds, but is this generally true for isotopes of all elements? (By isotopes I mean stable ones with large half lives.)
3
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3answers
252 views

Mass Spectrum and Molecular Ion peaks

If a molecule contains four chlorine atoms, how many molecular ion peaks will this compound show in its mass spectrum?
2
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1answer
47 views

Placing the atomic mass and number of an element… [closed]

Why are the atomic and the mass numbers of an element flipped in the textbooks relative to the periodic table?
8
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1answer
2k views

Does hydrogen really have seven isotopes?

I know that there are 3 isotopes of Hydrogen. But according to this website it is showing 7 http://periodictable.com/Properties/A/KnownIsotopes.htmlWebsite
4
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1answer
220 views

On the stability of deuterium

The isotope of hydrogen, tritium, is indeed radioactive resulting in He 3 through beta decay. But what of the radioactively 'stable' isotope deuterium? Are all deuterium atoms destined to be ...
2
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2answers
111 views

Would C bond with H or D?

Is a C-D bond better than C-H bond? I mean if carbon has a chance to either for a bond with deuterium or hydrogen what would it choose and why? What if tritium competes too?
8
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2answers
509 views

Where does the molar mass difference between Nâ‚‚ and CO come from?

The molar masses of $\ce{N2}$ is 28.0134 g/mol, for $\ce{CO}$ it's 28.0101 g/mol (WolframAlpha computation). Of course, they do have the same mass in atomic units (28). My question is, where does ...
7
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1answer
282 views

Is there a simple way to separate deuterium oxide from tap water?

I understand that tap water contains minute amounts of deuterium oxide (heavy water). Is there a simple way to separate, concentrate the $\ce{D2O}$?
6
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3answers
314 views

Are radioactive isotopes of silver dangerous?

I know we all think of things like uranium as being radioactive in the nasty radiation poisoning sort of way. But do elements like silver have similar effects in their radioactive isotopes? I'm an ...
3
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2answers
52 views

Can carbon dating tell how long a species would survive?

Carbon ($\ce{^{14}C}$) is used to determine how long a particular species has lived or how old it is. Can we use the same isotope to derive how long a species may survive? (My understanding is still ...
11
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3answers
637 views

Biological Consequences of Asteroid Mining—Death by Isotope?

It's been documented that NASA hope to capture an asteroid in 2025, and have subsequent aims to mine that asteroid. If if this is successful, we would expect other asteroids to be mined in the future. ...
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1answer
111 views

Questions about combustion and isotopic abundance

the combustion of 0.214g of sulfur provided exactly 0.428g of sulfur dioxide. After a second try, 0.782g of SO2 was obtained. What mass of sulfur was used? The combustion of lithium forms lithium ...
3
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2answers
4k views

The formula for finding the percentage of isotopes in an element's atomic weight?

In my class my teacher showed us how to find it, with a method, but he didn't really state the formula. I conjured up a formula from what I observed and it works. Here it is: $$ \frac{i_1x + ...
3
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1answer
101 views

Protactinium-234 half-life

This is going to seem like a rather daft question, but what is the definitive half-live for protactinium-234 (234Pa)? I'm seeing lots of different answers in various academic papers etc. For ...
8
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2answers
494 views

Is real water made up of heavy water and light water?

I need to know, is real water made up of heavy water which is formed with deuterium, and light water which is water by protium? We know that hydrogen has three major isotopes, including protium and ...
1
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1answer
95 views

Can I perform a stable isotope analysis at home?

I'm interested in measuring the stable isotope ratios of some bird feathers. I'm aware that a mass spectrometer is required to measure stable isotope ratios. Is it possible to measure stable isotope ...
0
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1answer
32 views

What does $\mathrm{A}_r(\mathrm{H})$ represent when calculating the average natural weight of an elemental atom?

I have a question that explains the weights and abundances of various hydrogen isotopes, and the question concludes by asking to: Calculate the atomic mass of hydrogen $\mathrm{A}_r(\mathrm{H})$ ...
8
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4answers
649 views

Chemical properties of isotopes

I've always heard that different isotopes of the same element have exactly the same chemical properties. But for example, I've read that some compounds which have hydrogen atoms interchanged by ...
11
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1answer
614 views

What is deuterium-depleted water actually used for?

I noted, flipping through the paperback Alfa Aesar catalogue today, that they sell deuterium-depleted water. Under the usage category, they list 'NMR'. I'm trying to work out what specific use this ...
12
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4answers
471 views

Is there a simple field test for heavy water?

Thought experiment Given two glasses of water, how would one detect which glass contains heavy water, and which contains potable water without using complicated laboratory equipment? Something like ...