Smallest particle still characterizing a chemical element. It consists of a nucleus of a positive charge, carrying almost all its mass and electrons determining its size. This tag should be applied to questions that specifically concern these particles and their properties.

learn more… | top users | synonyms

1
vote
2answers
61 views

Does Bohr's theory violate the Uncertainty Principle?

In a book, it is stated that one reason for the failure of Bohr's theory was the fact that it violates the Uncertainty Principle. Is this fact true? if so, explain to me how it violates the ...
0
votes
0answers
20 views

What determines the color of a object? [duplicate]

Why is gold yellow for example? Which property of the atom determines the color?
11
votes
3answers
2k views

How do I visualize an atom?

I have searched and searched, oh how I have searched. I am looking for a 3-dimensional visualization of a whole (i.e., moderately complex; hydrogen is just a ball) atom that includes orbital ...
6
votes
0answers
55 views

Did anybody question the indivisibility of the atom because there were “too many” elements? [migrated]

The realisation that the atom was divisible, and thus that elements were not the "fundamental building blocks" arguably began around 1897 with J. J. Thomson's discovery of the electron and proceeded ...
2
votes
1answer
50 views

The proper explanation for the general formula of the DU? [duplicate]

I found a formula for the degree of unsaturation (DU) in Clayden’s Organic Chemistry. It explains, simply, the unsaturation with the difference in H atoms. Then I stumbled upon the general formula: ...
0
votes
0answers
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 ...
1
vote
1answer
406 views

How does sulphur has atomicity 8 [duplicate]

How does sulphur has atomicity 8, when its valence electrons are 6 like oxygen- ie even 2 sulphur atoms can share a pair of electorns and acheive the octet rule,why it should involve 8 atoms
3
votes
2answers
101 views

Question about quantum mechanical model of atom and the quantum numbers

I studied Bohr's model of atom and then the drawbacks of it and then quantum mechanical model of atom. Now quantum model is according to uncertainty principal and dual nature of matter and it says we ...
4
votes
1answer
25 views

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 ...
7
votes
0answers
87 views

Which elements can be diatomic?

Which elements can be diatomic and why? Motivation I shall discount the noble gases as they do not usually form bonds anyway. Looking at the non-metals. See below. Hydrogen, Nitrogen, Oxygen and ...
4
votes
1answer
52 views

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.
2
votes
1answer
359 views

Element with No Proton?

On seeing this graph closely I noticed the there a element with no proton. But with no proton there will be no electron too and don't think that an lone neutron would form an element. So is that ...
0
votes
1answer
34 views

units of mass on the atomic scale

what are the systems of recording atomic masses and their units? I know that the nucleon number is the number of protons and neutrons I also know that the mass number on the periodic table is the ...
3
votes
1answer
137 views

electron passing nodes?

When one say that the electron goes from 1 orbit , say 2S, to another (higher) orbital, say 5P, it mean that the electron is excited to that orbit by some mean. In doing so it also it will also cross ...
0
votes
1answer
54 views

Electron vs electron density

I recently read somewhere that electrons do not exist. it's just the electron density. Is it true that there are no electrons (particles) but only in the form of electron density? And does this ...
1
vote
1answer
43 views

What is continuum in line spectra?

I read that continuum in line spectra is noticed beyond a certain limit. What does it mean?
2
votes
0answers
41 views

Is there an algorithm for ascertaining the relative size of an atomic/ionic radius?

To the best of my knowledge, the following properties affect atomic radius. The grounded-state size of the valence electron shell. The Coulomb force of the core electrons less the Coulomb force of ...
3
votes
1answer
112 views

Why do ion cores not move in a metal?

The delocalized electrons in a metal move about because of the electrostatic attractions between them and many different positive ion cores. But why does the same not occur with the ion cores ...
1
vote
0answers
43 views

Molecules from atoms [closed]

Why do two oxygen atoms combine to form a molecule and not 3 or 4? Also, why does one sodium and one chlorine atom combine to form $\ce{NaCl}$ while two chlorine atoms are required to combine with one ...
3
votes
1answer
65 views

Calculating edge length of a cube atom

This question comes straight from a worksheet we were assigned in chemistry, though it’s more math focused of a question I hope that this is an appropriate question to ask here. Calculate the edge ...
7
votes
1answer
77 views

Why is Astatine monoatomic?

I learnt that halogens always form covalent bonds to becoms diatomic molecules. So why is astatine monoatomic? I mean they have the same properties, why shouldn't they all be diatomic?
7
votes
1answer
548 views

Really how rare are hydrogen atoms?

Hasok Chang, a chemist, but perhaps more a philosopher recently published the book Is Water H2O? . Chang used the question and an extensive web of arguments ultimately as a platform to support a ...
1
vote
0answers
81 views

How many hydrogen atoms are in a sample of NH3?

How many hydrogen atoms are contained in 8.66 moles of $\ce{NH3}$? The answer is given after the log has been taken, so the final answer is 25.19. What I have been doing is multiplying 8.66 by 6.02 ...
2
votes
1answer
43 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?
6
votes
1answer
104 views

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?
2
votes
1answer
44 views

Atomic number $Z$

If electrons were spin-$\frac {3}{2}$ instead of spin-$\frac {1}{2}$ , what would be the atomic number $Z$ for the first noble gas ?
3
votes
2answers
84 views

Why does ionization energy increase as we go from left to right in a period?

Why does ionization energy increase as we go from left to right in a period? In my textbook, the explanation is as follows: "This is consistent with the idea that electrons added in the same ...
6
votes
2answers
51 views

Interaction radius of a molecule

What is the most commonly used radius of an atom or molecule to describe the area that must touch another area of another molecule for the two to react. Is there one radius that always works or does ...
4
votes
1answer
155 views

Usefulness of the outdated Bohr model?

Whilst the Bohr model is incomplete and incorrect, it had limited usage in predicting spectral lines. In the same way, could it possibly with limited accuracy, be used to predict the outcome of ...
5
votes
1answer
52 views

How was it determined that the electron observed in the cathode ray experiments was the same particle that gave an atom its balancing negative charge?

How was it determined that the electron observed in the cathode ray experiments was the same particle that gave an atom its balancing negative charge? Couldn't there have been an entirely different ...
1
vote
0answers
127 views

Diatomic Molecules/Elements

What is the difference between diatomic molecules and elements? Also, If oxygen is element of a single atom, then what makes it a diatomic element? But, then I read that a single oxygen atom can ...
5
votes
1answer
403 views

Why are so many wave functions associated with hydrogen?

According to Wikipedia, there's an infinite set of possible wavefunctions (orbitals) for the hydrogen atom: $$\psi_{n\ell m}(r,\theta,\phi) = \sqrt {{\left ( \frac{2}{n a_0} \right ...
1
vote
1answer
45 views

How do atoms combine? [closed]

Do atoms combine with the nearest atoms possible because of lower delta E (less energy needed to form a stable nucleus)?
3
votes
1answer
94 views

Are the energies of orbitals that are not filled in an atom, equal?

In a hydrogen atom only 1s orbital is filled. Does this mean that the energies of all other orbitals are equal? If so,why?
4
votes
1answer
64 views

Isn't the mass of a carbon 12 equal to a mass of 6 neutron + 6 proton + 6 electron?

The mass of Carbon 12 is 12u from definition, and is formed with 6 neutron, each with 1.0087u, 6 proton, each with 1.0072u and 6 electron, each with 0.0005u, which all add up to 12.0894u. why is there ...
5
votes
1answer
60 views

How were the absolute masses of atoms calculated before the mass spectrometers?

I understand that true (non-relative) masses of atoms are calculated with a mass spectrometer. using this relationship: Centripetal Force = Force due to magnetic field(B) But I was wondering how ...
0
votes
0answers
21 views

Correlation between crystal structure and underlying atomic properties

Can the crystal structure of an element/metal be explained by any underlying atomic or quantum mechanical properties of the element or is it an intrinsic property by itself (like atomic number)?
0
votes
1answer
123 views

Can we make Gold in a Lab? [duplicate]

Can we make Gold in a Lab? Is it possible to make changes in metals that will create Gold? and How? I have tried to search something related to this but didn't get any good results. Thanks in Advance
2
votes
2answers
38 views

Does Uranium ore count as a mixture?

I'm doing an assignment where we must research the separation of a mixture to obtain a useful final product. I thought about the separation of Uranium from its ore after it has been mined, but I did ...
5
votes
1answer
140 views

Do multielectron atoms have nodes?

For hydrogen, other than in the 1s state, the electron wavefunctions have radial and/or angular nodes where the electron probability density is zero. In helium or further atoms with more than one ...
6
votes
0answers
70 views

Density Functional Theory with Generalized Gradient Approxmations (GGA) - What Happens if the Electron Density Shows a “Kink” at the Ion Position?

My question may be stupid, so please correct me if you find anything which is obviously erroneous. In the following I will place a question mark (?) besides points/steps I consider doubtful. My ...
3
votes
0answers
29 views

Signs of Exchange and Correlation Potentials

The exchange and correlation potentials refer to those defined in density functional theory. (See also http://en.wikipedia.org/wiki/Local-density_approximation) Define the exchange potential as ...
2
votes
1answer
120 views

Electron Configuration of an element with no. of electrons > 18

Let's say that we have an element, say $\ce{Ca}$. According to law, the last shell should contain only upto 8 e-. Hence, electronic configuration of $\ce{Ca}$ would be 2,8,8,2. But, according to the ...
2
votes
2answers
73 views

Molecular Assembly Program

I'm not totally sure which Stack Exchange community this would go in, but Chemistry seemed best. I've been thinking for a long time now, that it would be cool to have a program where you could design ...
9
votes
1answer
1k views

Is the atom the smallest particle, which takes part in chemical reactions?

According to modern atomic theory, the atom is the smallest particle which can take part in a chemical reaction. But during the formation of hydronium ion, $\ce{H+}$ ion reacts with $\ce{H2O}$ to form ...
3
votes
3answers
200 views

Why do no known atoms have electrons in the g or h subshells?

I'm learning about orbital quantum numbers. While checking several elements on the periodic table I noticed that there aren't any atoms that have electrons in the g or h sub-orbitals. Why is this?
1
vote
1answer
41 views

Atomic mass ratios - Is the problem providing enough info?

1 gram of Hydrogen reacts with exactly (almost) 8 grams of oxygen to produce $\ce{H2O}$. 1 gram of Hydrogen reacts with 16 grams of Oxygen to produce $\ce{H2O2}$ can ratio $m_O/m_H$ be determined from ...
1
vote
2answers
100 views

“Editing” atom nucleus

First of all. I am really bad at chemistry and all that. So this might or more likely will sound at least primitive... But this question has been bothering me for far too long. So, I was reading about ...
2
votes
1answer
38 views

How are atoms manipulated?

I was wondering how scientists are able to handle atoms. They are very small, but surely people are able to interact with them somehow? The Large Hadron Collider is one example. Also, they try and ...
1
vote
1answer
27 views

Why does ionization violate the stable or lowest energy rule in atoms?

Electrons that fill orbitals always do so in such a way that the resulting structure has the lowest energy state possible, though there are anomalies like chromium and so on. But ionization no ...