The number of electrons in a human body

[Sapper]

To determine the number of electrons in a human body, one must first consider the relation between mass and electrons.

As we all know, electrons have an extremely small mass - this makes it impractical to use their mass to determine the total number of electrons in a human body.

Consider that in most cases (a general state) every electron in a body will be in some way paired up with one proton. Next, consider that typically, for every proton there will be a neutron.

Now consider that the mass of 1 proton is one a.m.u. (atomic mass unit).

Let the mass of a person be 60.0kg (132lb). Their mass in grams is: 60'000g or 6.00x10^4 g

the mass of one proton is 1 amu = 1.6607x10^-24 g

Now consider the number of amu units within a human body of 60kg mass: mass / amu mass = #amu units

6.00x10^4g / 1.6607x10^-24g = 3.61x10^28

Now in the consideration that every proton will be paired with a neutron, we must divide the # of atomic mass units to derive the number of protons alone:

3.61x10^28 / 2 = 1.80x10^28 protons

it therefore stands to reason that there are approximately 1.80x10^28 electrons in the human body

[jimk]

i can always tell when i don't have enough protons in my body, i feel really negative.

[Sapper]

LOL

[Lebell]

There is not a pure one to one relationship of protons to neutrons.

I think a better approach is to look at the overall composition of the human body and calculate the number of electrons based on this using Avogadro's number.

The human body is roughly 55-60% water (18 electrons) which is easy to calculate. I'm sure with just a little googling, I can find the rest of the percentages which are carbon, nitrogen, hydrogen and then varying trace amounts of heavier elements such as iron, copper, zinc, etc.

[Sapper]

Actually .. you are FAR more likely to have an equal number of protons and neutrons than you are protons to electrons. This is all mathematical average anyways - considering that there are three common carbon isotopes in nature.

The above method has widely been accepted as the most accurate. Using percent composition will not account for biological variances in trace elements whereas the AMU method will - based on using mass vs. %

[Lebell]

Originally posted by Sapper
Actually .. you are FAR more likely to have an equal number of protons and neutrons than you are protons to electrons. This is all mathematical average anyways - considering that there are three common carbon isotopes in nature.

The above method has widely been accepted as the most accurate. Using percent composition will not account for biological variances in trace elements whereas the AMU method will - based on using mass vs. %

Tell you what, give me a link so I can research it myself.

And I didn't expect to get into a debate in "Knowledge", but there is a one to one relationship of protons to electrons in an atom (not ion) BY DEFINITION. So while low Z elements corrolate closely on the number of protons to neutrons, they will ALWAYS be the same when it comes to electrons and protons.

For example, sodium has 11 electrons and 11 protons but 12 neutrons.

[Sapper]

That is fine - what you are too proud to accept is that within mathematical average, there will be a 1:1 pairing.

There are sufficient P+ isotopes in the body to counter the N+ isotopes by average mass. You method introduces error in an almost exponential fashion as compared to mine.

Think back to your method, then think back to propogation of error.

[Lebell]

Don't take this the wrong way but,

Do you know anything about chemistry?

Isotopes are created solely by varying the amount neutrons, never by changing protons.

If you change the number of protons, you change the element.

[Lebell]

And yes, I've been wrong on things, (and not too proud to admit it) but dude, this is Chemistry 101 we're talking here...

[Sapper]

I know exactly what isotopes are! When I refer to P+ isotopes, you likely think that I am referring to additional protons being added .. this is because you have clearly never done any atomic physics. Two very common methods of comminucating isotope types:

N+, N- (and) N+, P+ both of which mean the same thing. That is to say, P+ = N- ... think nuclear "dell" if you still don't understand what I am saying.

I appreciate your tactfulness in asking whether or not I understand chemistry . It is extremely difficult to properly convey "tone" over a "toneless" medium.

[Lebell]

Well, I'm always happy to learn new things and since I've only gone through Physics 2 and P-Chem, I'll be happy to learn some new nomenclature, but I wasn't able to find what you are describing on the net. (Although I can have an enthusiastic talk about spectral analysis with you, especially using XRF)

But how can you say that the ratio averages to 1:1 when the ratio never dips below 1:1? Your culmulative error will always be on the plus side for neutrons.

[maxero]

significant figures and all

[stingc]

Sapper,
There are an equal number of protons and electrons in the human body. This is obvious directly from Coulomb's law. Even a miniscule charge imbalance would generate huge forces that clearly do not exist.

Why are you worrying about isotopes? Just use the the masses given in any periodic table. These already correctly weight all the different isotopes in their natural abundances. Our bodies do not hoard particular isotopes (at least not significantly).

The human body is mainly carbon, oxygen, and hydrogen. These have 6, 8, and 0 neutrons respectively in their most common isotopes. Less common ones are very rare, and can be neglected. Standard chemical groups - CH(n), COOH, etc clearly have more mass in the carbon and oxygen atoms than in hydrogen, so the proton:neutron ratio will be pretty close to 1. The proton:electron ratio is however extremely close to 1.

[Sapper]

Stingc,

I am not worried about isotopes. In fact, my initial position is that there will be an isoelectric equalibrium in the human system.

Lebell,

It is akin to assigning charge numbers to elements (ie. Na 2+ being the same as Na +2). P+ simply means that there are more protons than neutrons as a result of nuclear chemistry in action.

A-ray fluorescence spectometry .. cool development in analytical chem! I've read a few journals regarding XRF and VOC detection - hell of a lot better than doing combustion analysis!

In any event, physical theories asside ... with 3 sig. figs of precision, any imbalance in N+ and neutral isotopes present is well within the error range afforded. You may not agree with my method .. however, surely you can appreciate that it is both: more elegant, and more reliable than calculating percent composition, etc .. and then finding the number of e- present from the derived data.

[TUDelftstudent]

I ran into this thread while I was searching for info on the following question:

"What would your net charge be if the proton and electron charges were 1 billionth part of their own charge apart?"

It was easy to calculate the amount of protons and neutrons in the human body, basically there is a 50-50 spread and they have approximately the same mass. The mass of electrons can be neglected as it is tiny.

Thinking about the physics behind it, if there is only a slight difference between charges, massive forces arise. That alone makes enough sense to defend the statement there is an equal number of protons, neutrons and electrons in the human body.

I in fact calculated what would happen if the charges were different by just 1 billionth of the electron charge (and the net charge wouldn't be 0). A human body of 75 kg would get a charge of 3 Coulomb.

Assuming Coulomb's law would work for two humans pretending to be particles, at a 1 metre distance there would be a force of 81,000,000 Newton. Enough to accelerate you to the moon in under a second.

Clearly it's not the case, there are approximately as many electrons as protons.

[BadNick]

Thank you...I read the above and feel more enlightened about this interesting question.

It also made me wonder if I may have a rare Coulombular imbalance that results in repulsing many positive women.

[telekinetic]

I like the part where we assume a human body is 138lbs, and then argue over specific masses of isotopes.

[Plan9]

"P for plenty!"

[Zeraph]

An electron sitting in a prison asked a second electron cellmate, "What are you in for?" To which the latter replied, "For attempting a forbidden transition."



Outside his buckyball home, one molecule overheard another molecule saying, "I'm positive that a free electron once stripped me of an electron after he lepton me. You gotta keep your ion them."

[marym]

by the way the mass of 1 amu is equal to 1.66x10^-27 not 1.66x10^-24

[Daniel_]

There are at least seven.

[kutulu]

Originally Posted by Lebell

There is not a pure one to one relationship of protons to neutrons.

I think a better approach is to look at the overall composition of the human body and calculate the number of electrons based on this using Avogadro's number.

The human body is roughly 55-60% water (18 electrons) which is easy to calculate. I'm sure with just a little googling, I can find the rest of the percentages which are carbon, nitrogen, hydrogen and then varying trace amounts of heavier elements such as iron, copper, zinc, etc.

The proton to neutron ratio REALLY doesn't matter when the total is on the order of 10^28. It isn't an order of magnitude difference and that's all that really matters.

Originally Posted by telekinetic

I like the part where we assume a human body is 138lbs, and then argue over specific masses of isotopes.

Same thing, it's a meaningless detail when you are talking about a number that big.

[prudence12]

Originally Posted by jimk

i can always tell when i don't have enough protons in my body, i feel really negative.

LOL!!!