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Questions tagged [atoms]

Smallest particle still characterizing a chemical element. It consists of a small nucleus charged positively, carrying almost all of the atom's mass, with electrons surrounding it. This tag should be applied to questions that specifically concern atoms or their properties. For the charged particles, please use [ions] instead. If your question is specifically about [protons], [neutrons], or [electrons], use those tags instead.

From the IUPAC GoldBook, an atom is the:

Smallest particle still characterizing a chemical element. It consists of a nucleus of a positive charge (Z is the atomic number and e the elementary charge) carrying almost all its mass (more than 99.9%) and Z electrons determining its size.

This basic unit of baryonic matter, that consists of a dense central nucleus, i.e. and , surrounded by a cloud of negatively charged is electrically neutral.

Note that questions about nuclear physics are most suited on Physics.SE instead.

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Are atoms really round?

I'm not sure if this is a silly question, but I was sitting here with a cup full of cheezey poof balls thinking, "My goodness, it's like an amazing cheesey delicious liquid - huge water molecules!" Of course my next thought was, "Wait a minute -…
Wayne Werner
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Is it possible to have a diatomic molecule of sodium in gaseous state?

Already I know that hydrogen, all the halogens, nitrogen and oxygen forms diatomic molecules. But I am confused about $\ce{Na}$? So I would like to know about that.
On the way to success
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Is atomic weight universal?

Are we advanced enough to calculate the abundance of an element throughout the universe or is our atomic weight only based on the occurrence of an element in our planet alone?
Pre-alpha
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Why aren't atomic radii calculated using Schrödinger's equation?

The atomic radii are estimated using a variety of methods: most of these involve dividing their bond length by 2. But that is a very crude way of measuring atomic radii. I mean, atoms overlap each other when bonded, surely the actual atomic radius…
Gerard
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What is there in an atom between the nucleus and electrons?

As you can see the atom consists not only of the nucleus and electron but also of "empty space is the space empty or is their something else?
A.R.K
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Deflection of Alpha Particles in Rutherford's model of atom

Rutherford stated that deflection of alpha particles is due to repulsive positive charge of nucleus. Why can't alpha particles be deflected by attraction of so many electrons revolving around nucleus?
Muhammad Hashim
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What do atoms look like?

A professor of mine noted that when he was in school, microscopes weren't powerful enough to resolve certain things (I forgot what it was). But current microscopes are powerful enough. Extrapolating from this trend, he hypothesized that by the time…
Dissenter
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Conversion atom to another

One child has claimed to have find a solution to all physical problems. On asking for details, he said that all periodic elements has common components, i.e. electrons, protons, neutrons. The child has suggested a solution: convert atom to another…
RAM
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Z* effective charge and Ionization Energy

I'm trying to figure out the patterns for Ionization Energies. I am familiar with the periodic trend, however things become quite different when we hit the 1st I.E. For example, Na has an I.E(1) of 495.8 kJ while its second I.E. rockets up to 4562…
Dimitri
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Can atomic number change the type of electromagnetic radiation being emitted when a electron drop from a energy level to another?

Without getting into too much/any math, I just wanna talk about intuitions if possible. If atomic increase, the attraction increase, and consequently the potential energy increase. More energy leads to higher frequency, different radiations. I…
user134789
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How many atoms are represented in this equation?

$\ce{Pb(NO3)2 + 2KI -> PbI2 + 2KNO3}$ The answer says 26, but shouldn't it be 13? Because actually, the number of atoms involved in the reaction are 13, and once the reaction is completed, again, number of atoms is 13. Please explain.
magikarp
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What is 'space'?

What is in the space between atoms? I understand that molecules are constantly being formed from collisions and such, but what I do not understand, is, on a tiny level, within the level of the atom, what is in between? 'Air' is not the answer, what…
Equinox
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The mass of carbon atom

I was reading Silberberg's principles of general chemistry when I noticed that it says that the mass of carbon12 is exactly 12 amu. But when I calculated the total mass of its components (6 protons : 1.00727 amu each , 6 neutrons : 1.00866 amu…
Ali
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Different masses for the same element and isotope?

I am watching this Khan Academy video on mass defect and binding energy, it uses helium-4 as an example to go through the concept. The person finds the predicted mass (protons + neutrons) to be 4.0318274 amu. He also finds that the experimentally…
karmstr7
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Is the boundary of an atom well defined?

That question might seem weird, but that's what I have been imagining lately; going through Bohr's theory on the hydrogen atom. He clearly defines the radius of an orbit with an exact mathematical expression. But what do they mean when they say any…
YourAverageEuler
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