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.
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Why does increasing subshell cause ionization energy to decrease?
I know that increasing subshell decreases ionization energy; for example, going from Beryllium to Boron. I do not understand why this is.
The answer my textbook (Chemistry 2e on OpenStax) gives is ...
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respective posistion of d and p orbitals in a multielectronic species
we write the electronic configuration of atoms as [noble gas core]4s2 3d10.that is that due to energy considerations(aufbau principle) in multielectronic species.
what i want to know is whether the 4s ...
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Lother Mayer curve
While studying about atomic trends, I encountered the Lothar Meyer curve:
If the covalent radius decreases across a period, why is the graph of atomic volume reaching local minima halfway in the ...
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The ambiguity regarding aufbau principle
According to a Blog https://ericscerri.blogspot.com/2012/06/trouble-with-using-aufbau-to-find.html
written by Dr.Eric Scerri,
On moving from the $\ce{Sc^3+}$ ion to that of $\ce{Sc^2+}$ it is plain ...
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How to derive the number of spectral lines?
Recently, I found that when electrons in an atomic sample de-excite from a higher energy level ($n_2$) to a lower energy level ($n_1$), the number of spectral lines observed in the spectrum is
$$\frac{...
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Does the Atomic Mass listed for each element on the periodic table reflect the relative abundances of their isotopes on Earth? Or in the Universe? [duplicate]
Somehow, I cannot find a site or book or paper explaining exactly how the average atomic masses for the elements on the periodic table are weighted....
I posted a question either here or on Physics S....
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How is the molar weight of C-12 equal to 12 gram ? Why is "g" not considered while calculating molar weight? [closed]
So, I was just pretty confused about how we simply multiply the "mass" of total nucleons in Carbon by the Avogadro Constant, to get the molar "weight" as 12 grams, shouldn't it be ...
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How is most probable radius in quantum mechanical model equal to Bohr's radius in hydrogen atom
Most probable radius in 1s orbital for hydrogen electron is $\pu{0.529E-10 m}$ which is Bohr radius. But energy of electron in hydrogen atom is proportional to mean radial distance in atom. In this ...
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what does it mean to say oxygen in a given context?
My textbook "chemistry by Julia" says the following
When it comes to expressing the molar mass of elements such as oxygen and hydrogen,
we have to be careful to specify what form of the ...
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What would happen if the alpha particles directly hit the electrons in the gold foil in Rutherford's experiment? [closed]
What would happen if the alpha particles directly hit the electrons in the gold foil in Rutherford's experiment?
Would it get ionized or is there no probability of such a thing happening ?
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Why are electrons filled in fourth shell before the third shell is filled?
I am a beginner and am learning about atomic structure and I am getting confusions regarding the aufbau principle.
It is said that the electrons will be filled first in lowest available energy level. ...
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If an atom had 200 protons, how much neutrons would it need to have to be most likely stable and why?
I know there is a specific proton/neutron ratio but i'm unaware if it applies to atoms with 86 protons and beyond.
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Why is atomic mass unit/unified atomic mass defined against Carbon 12?
I have searched the web all over this question and I have not really found an answer to my satisfaction. From my understanding of the topic so far, I understand that reason why concept of unified ...
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When is the n+l rule followed when working with energy of different orbitals?
While going through my book, I came across a problem which gave some options about the order of energy of 3s, 3p and 3d orbitals of hydrogen atom. The correct answer was given as:
3s, 3p and 3d ...
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Atoms vs molecule when talking about the avogadro's number? [duplicate]
By far, my understanding is that a molecule is made up of atoms bonded together. For example, a molecule of water ($\ce{H2O}$) has 2 hydrogen atoms and one oxygen atom.
However, when it comes to ...
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Why electrons do not distribute evenly among the atoms in a molecule? [closed]
I was wondering why the state where electrons are evenly (or the closest to being evenly) distributed among the atoms in a molecule is not the lowest energy state? For example, in a water molecule it ...
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Rutherford's Alpha Ray Scattering Experiment & Plum-Pudding Model
My teacher said, "Rutherford thought that all the Alpha particles would directly go through the gold foil without any collision if the plum pudding model was right. Because, as said in plum ...
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Schrodinger's Equation and Wave Function
So I understand that there exists the shrodinger's equation, which on solving,gives the wave function of an electron. The wave function as I understand, gives all possible information about an ...
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Is this bond Ionic or Covalent, and why? AlBr [closed]
We know a compound could form between NaCl because they are +1 and -1 ions which make them both into a complete valence set.
Could a compound form between Al and Br, for example, and what type of bond ...
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Does the electron in a neutral hydrogen atom ever exist in the p, d or f sublevels?
I learned that the electron in a neutral hydrogen atom can be excited to higher levels. But there are different sublevels in the levels. For example s, p, d and f.
Does the electron only jump from s ...
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Why do electrons jump back after absorbing energy and moving to a higher energy level?
Electrons in a shell absorb energy and move to higher energy levels, but they release their energy and jump back to the shell they originally were in. Why do they jump back? Why can they not keep ...
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Why is the ionic radius of hydride so large?
The order of ionic radii for halides and hydride is apparently as follows:
$$\ce{F-} < \ce{Cl-} < \ce{Br-} < \ce{H-} < \ce{I-}$$
Why is the hydride ion so large, even larger than bromide ...
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What does orbital mean, exactly? [duplicate]
My teacher told me that orbital is the probability distribution data of the electron around nucleus which is amplitude data in a way.
An example of how my teacher actually told what it means involves ...
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Why is the atomic mass unit less than the mass of both a neutron and a proton? [duplicate]
The atomic mass unit is $1.6605 \times 10^{-27}$ kg.
This is less than the mean of the masses of 6 protons and 6 neutrons.
How do we account for the lower mass ?
My understanding is that some of the ...
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Does electron mass decrease when it changes its orbit?
I have studied this in my chapter atomic structure that when an electron changes its orbit from lower energy to higher energy state , it does not state in my book that it moves there but that it ...
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How is this possible in mole concept? [closed]
L = $6.022*10^{23}$
If I have one atom of oxygen , it has exactly L value.
Now 2 atoms of a oxygen have 2L value.(Note that I mean 2O and not $O_2$here)
Well , if we take a molecule made up of 2atoms ...
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What does Pauli’s exclusion principle mean in atomic or fundamental way? [closed]
It means is that no electron can have same n , l and $m_l$ but can have two different spin quantum number.
I want to know why is this rule valid?Means there must be some other things happening also ...
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Is this diagram correct for difference between 2N and N2
There is 1 $\ce{N2}$ molecule formed with 2 atoms of nitrogen.
2N is 2 separate nitrogen atoms which have not formed any bond.Reasons could be that they didn’t get enough energy to form bond so they ...
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Why do Rydberg atoms have electrons that can transition above the first ionization energy?
Why do Rydberg atoms have electrons that can transition above the first ionization energy?
This can only happen in a multi-electron system but I don't see how the Rydberg formula would even work for n ...
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Why hydrogen gas tube produce hydrogen atomic spectrum
To measure the atomic hydrogen spectrum people often uses hydrogen gas tubes as light source.
Since the gas in the tube is the molecule $H_2$ , why we obtain the spectrum of atomic hydrogen?
My guess ...
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Why does matter have spaces between them? [closed]
If you mix sugar Crystal in a glass of water and mix it well, the level of water will not rise.The reason they say is that matter have spaces between them.If matter have spaces between them , How ...
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"Isotopes" in a molecule?
I just learned that atoms of the same element can have different mass because of they are isotopes. If there are two isotopes in which each reacts to form the same thing. Would the mass differ in each ...
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Hydrogen and Hydrogen ion
Is it correct that a hydrogen atom only has 1 electron and 1 proton since the atomic mass is 1?
Also, is the hydrogen ion composed of a single proton and no electrons?
In an ionization process we know ...
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Reason for needing multiple radii for the same atom [duplicate]
Why do we need different types of atomic radii? Why can't there be just one radii for an atom?
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In metallic bonding, what causes a metal to lose its outer electrons and become an ion? [duplicate]
In metallic bonding, what causes a metal to lose its outer electrons and become an ion? I am trying to understand metallic bonding, atoms and ions.
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Why does covalent bonding not break down if observer effect can be applied to atomic electrons? [closed]
The observer effect in quantum mechanics states that when unobserved, quantum particles such as electrons can simultaneously occupy two different states. In an atom of any element, where there are ...
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Does the 4s orbital really have a higher energy level compared to 3d? [duplicate]
For writing the electronic configuration of the $\ce{Fe^2+}$ ion, you need to remove two electrons (as it is an ion) which are from the highest energy level.
Apparently, this would be $\mathrm{4s}$ ...
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Could observer effect cause electrons in one orbital to be found in another?
The observer effect states [1] that
when unobserved, absolutely small particles like electrons can simultaneously be in two different states at the same time.
If we look at an atom of any element, ...
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Rules to follow while writing a chemical formula for polyatomic ions
In Science, textbook for class IX, chapter $3$ [1,p.38], it states:
The rules that you have to follow while writing a chemical formula are as follows:
in compounds formed with polyatomic ions, the ...
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Illustrating moles with sand grains, Are there more moles of SiO2 in a grain than moles of sand on the earth
I have been trying to understand the scale of atoms, thinking about sand grains as an example.
With approximately $7.5\times10^{18}$ grains of sand on the earth that is $1.25\times10^{-5}$ moles of ...
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How did Mendeleev know elements from compounds or mixtures?
I read that Mendeleev initially thought didymium was an element, but it was actually a mixture.
How did he know the rest of the chemicals in the periodic table were elements and not compounds, ...
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Confusion with definitions of mass [duplicate]
What is the difference between:
atomic mass
relative atomic weight
relative isotopic weight
standard atomic weight
atomic weight
relative atomic mass
I am told by Wikipedia that:
relative atomic ...
user96130
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What is the dimension of Avogadro's constant?
What is the dimension of Avogadro's constant ($N_\mathrm{A}$).
On Wikipedia it says it is dimensionless, but in Nigel Wheatley's article (pdf) On the dimensionality of the Avogadro constant and the ...
user96130
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While calculating the effective nuclear charge, why don't we consider effect of outer electrons on inner ones? [duplicate]
When calculating the effective nuclear charge for an electron, why do we only consider the repulsive effect of the inner electrons on the outer electrons? The outer electrons also repel the inner ones ...
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What were the expectations of Rutherford's gold foil experiment? [closed]
At the time when Rutherford's gold foil experiment was performed, Thomson's plum pudding model was believed to be true (at least by Rutherford himself and his students).
With this model in mind ...
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How do orbitals overlap in difluorosilane? [closed]
In $\ce{SiH2F2}$ four orbitals of silicon $(\mathrm{3s},$ $\mathrm{3p}_x,$ $\mathrm{3p}_y,$ $\mathrm{3p}_z)$ overlap with two hydrogen $(\mathrm{1s})$ and two fluorine $(\mathrm{2p}).$
I want to know ...
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How to compare size of subshells?
For the same principal quantum number, on increasing the value of the azimuthal quantum number does the average radius of the subshell increase or decrease?
In other words, which out of, say, 3s, 3p, ...
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Are atomic mass unit (amu), unified mass unit (u) and Dalton (Da) the same unit but with different names? [duplicate]
I recently read up on some chemistry and found these units of mass:
atomic mass unit (amu)
unified atomic mass unit (u)
Dalton (Da)
Are they all the same unit but just with different names or are ...
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Trend in atomic volume across a period [closed]
"Atomic volume decreases along a period, reaches a minimum at the middle, and then increases for the rest of the period"
Why does the atomic volume, along a period, initially decrease, ...
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Why doesn't core charge increase down a group? [closed]
Atomic radius increases down a group because the electrons feel a lesser attraction to the positive nucleus (due to shielding from inner shells). Why then, doesn't core charge decrease seeing as core ...
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