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 are the electrons revolve in orbits around the nucleus in an atom that are always circular while elliptical orbits are also possible [closed]
why Niels Bohr assumed that the electronic orbits are circular, Though orbits under inverse square law force are in general elliptical,(Planets move in elliptical orbits under the inverse square ...
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Can someone elaborate what it means when its said that electron shells do not exist in multi electron systems?
I'm an undergraduate student in chemistry. I'm trying to grapple with all the new stuff we're learning and making sense of it. Now I want to know if electron shells really "exist" in multi ...
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Why does atomic radius decrease across periods? [closed]
My textbook says that this happens because the number of protons, and thus the total positive charge, increases - a greater attractive force acts on each electron. The book says that this is despite ...
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Have we ever managed to "add" a proton to a nucleus? [closed]
I've tried finding answers to this via a simple Google search, but nothing has come up.
Have chemists or physicists ever tried "adding" a proton to an atom? For instance, add a proton (and a ...
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The first electron affinity of an atom
I've read that the first electron affinity is always negative, meaning that energy is always released upon the addition of this first electron. However, I don't think this will apply to noble gases. ...
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Masses of atoms and molecules [duplicate]
This is my understanding so far:
Average atomic mass is the mass of an element considering isotopes and is measured in atomic mass units. However relative atomic mass is the average mass of an atom ( ...
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If the effective nuclear charge of Beryllium(Be) is less than Sodium's(Na), how is the ionization energy of Be higher than Na?
According to Slater's rules the effective nuclear charge of Beryllium and Sodium is 1.95 and 2.20 respectively.
That means that the outermost electron of Na feels a stronger attraction from the ...
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How many carbon, hydrogen, oxygen, nitrogen, and phosphorus atoms are there in the observable universe?
If I could somehow reliably count all the carbon, nitrogen, hydrogen, oxygen, and phosphorus atoms in the observable universe, what number would I come up with?
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Is determination of nuclidic mass by nuclear reaction currently state of the art for any nuclides?
In Section 4.9 of Linus Pauling's General Chemistry Book (Dover 1988 edition, a copy of the WH Freeman and Company 1970 edition) he describes the principle behind the determination of nuclidic mass by ...
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If you give an electron in a subshell more energy, does it simply "jump" to the next energy level?
Suppose you have an electron in the $\ce{2s}$ subshell of an atom. If energy is given to it, does it simply jump to the next energy level (into the $\ce{3s}$ subshell), or does it move into $\ce{2p}$?
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Can it be said that an electron transfer between two neutral atoms comes from the neutral atomic electric field? [closed]
Let us consider the example of Na and Cl. Both atoms are called "neutral" simply because they have the same total number of protons as electrons, yet they have a very weak electric field ...
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Relative atomic mass calculation [closed]
In my textbook it states that relative atomic mass of an element Y is equal to the average mass off one atom of element Y multiplied by 12 divided by the mass of one atom of carbon 12.
What is the ...
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How are the number of neutrons changed in an atom? [closed]
I'm studying isotopes in high school and I don't understand how it works.
From my understanding, when neutrons are added or removed, an isotope is created.
To calculate the number of neutrons, the ...
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Why does the same electron transition release photons of different frequencies for some elements?
Question: For elements in the same period with different numbers of valance electrons, why does the same electron transition release photons of different frequencies?
Example: For valance electrons ...
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How can Planck’s equation and the wave equation simultaneously coexist with contradicting each other? [closed]
The equations:
E=hf (Planck’s equation, where E is the energy, h is the Planck’s constant and f is the frequency) and
V=fλ (where v is the speed (in a vacuum), f is frequency and λ is the wavelength) ...
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Why are ions in a mass spectrometer accelerated through electric plates? [closed]
I was reading an article on the AP Chemistry course in Khan Academy about mass spectrometry, which had this:
... ions are then accelerated through electric plates and subsequently deflected by a ...
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Can an element be a single atom or a molecule made up of atoms of the same element?
Some online websites and some books as well suggest that elements are either atoms (e.g. Ne) or molecules (e.g. $\ce{H2}$, $\ce{O2}$).
Original source: Tro, Chemistry: A Molecular Approach (2008)
...
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What is the energy difference between inner subshells?
For exemple, in silver the energy difference between the 4d 5s subshells is ≈ 4 eV (in the ultraviolet region, that's why it has no color, etc.), but what is the energy difference between some of its ...
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How do I calculate q/m? [closed]
My chemistry book (Mortimer in German) has the following question:
Calculate the value q/m for the following Ions:
("mit Masse" meaning "with mass")
How do I calculate q/m?
Thanks ...
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where could I find the standard atomic orbital energy of all elements?
I am trying to find the standard atomic orbital energy of all elements.
Here is the data I found in some old books:
I am looking for some more modernized data, I tried to look for the data in the CRC ...
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What does it mean when we say an atom has infinite energy levels/shells? [closed]
My chemistry teacher told that an atom has infinite energy shells according to Bohr model , where electron reside according to its angular momentum and energy.
But in lower classes/ grades I have ...
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Why do atoms make bonds? [duplicate]
I have been studying chemistry for a long time in school till now, but, what I recently realised I do not understand is why do atoms really make bonds, why do they want to gain or lose electrons or ...
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Proof for equation of radial probability distribution curve
So my textbook says the equation for this is
$$P(r) = 4\pi r^2\Psi^2 $$
It also gives the volume of the shell formula
$$\mathrm{d}V = \frac 43 \pi(r+\mathrm{d}r)^3 - \frac 43 \pi r^3$$
which I ...
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Size of Orbitals, Making Intuitive Sense of Quantum Model, Nomenclature of Subshells in the Quantum Model
Alright, so I am doing the Quantum Mechanical (or what some people call the Wave Mechanical model) of an atom. There's this part where we have different zones of the probablity of finding electrons, ...
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How do water vapor molecules push other air molecules away?
I've read that when water vapor enters the atmosphere, the vapor molecules push the oxygen and nitrogen molecules out of the way and occupy their space.
But if water vapor molecules are lighter than ...
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Restoring potential of atoms in a solid
Above $\pu{0 K}$ the atoms in a solid are vibrating. However, what kind of potential restores each atom in the starting position?
Consider the crystal lattice of NaCl. The potential energy of a $\ce{...
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Why isn't Beryllium a noble gas? [closed]
Somebody answered it before on physics StackExchange, but I couldn't follow the high-level parlance. All I could follow is that it is related to the p subshell. I cannot understand why elements form ...
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In Lanthanides, Why is electron removed from 4f before 5p? [duplicate]
I've been taught that electrons are removed first from valence shell electrons with highest energy. But In Lanthanides, for example taking configuration- [Xe]4f⁴6s², If we go to +3 Oxidation State, ...
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Why doesn't my estimation for the relative mass of a single lithium-7 atom work? [duplicate]
So I tried to calculate the relative mass of a lithium-7 atom. I added up the masses of all the protons, neutrons and electrons, like this:
mass = relative mass of 3 protons + relative mass of 4 ...
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How did we find relative atomic masses in 18th century or early 19th century? [duplicate]
The atomic masses of atoms or relative atomic masses were known in the 19th century.
But how did they actually calculate that relative atomic mass?
What I think is that if we have a sample of an ...
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How do the odd proton-number elements originate?
I have a question about the origin of the odd proton-number elements in the periodic table, please.
As it is generally thought that the big bang produces hydrogen first, and then hydrogen combined to ...
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What kind of electronic configurations are possible?
Let us take $d^6$ orbital as an example:
A) ↑ | ↑ | ↑ ↓ | ↑ | ↑ |
Now , this one 1 way. My Q is that how is it possible that in the 3rd box , we have a paired electron but not in the 1st one. Like it ...
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Why are the relative masses of isotopes not close to whole numbers?
Understandably, the relative atomic masses of isotopes are often not close to whole numbers as they're adjusted for isotope abudandancy eg. $A_r(Cl)\approx35.45$. However, wouldn't one expect the ...
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Can an atom bond with any other atom?
I am designing a game for students which has a sandbox for atoms to create molecules like building blocks. I have the valance of each atom mapped and they can bond with other atoms based on their ...
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What happens inside the orbital when energy provided to electron is not sufficient for it to change orbitals? [closed]
While studying the chapter called Atomic Structure, we were introduced with Bohr's model of an Atom. Even though not all of his postulates were right, I believe some were. A doubt arose in the ...
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What are the Ionic Properties of Co-ordinate Covalent Bonds? [closed]
In my 10th grade book, it says that
A coordinate bond has properties of both covalent and ionic bonds. Therefore, it is also called dative or co-ionic bonds.
I understand that it has properties of ...
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Shielding effect is not constant across a period [closed]
Shielding effect stays constant across a period because number of inner electrons stays the same.
Well, that's not true.
It only works for the period =1,2,3
but in period 4, the number of inner ...
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A better understanding of the screening effect and how it works?
What I am taught-
Inner shell electrons shield the outermost electrons from the attraction of nucleus. More closer the inner shell is to the nucleus, more its shielding effect. thus $n_s > n_p > ...
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Which atom is the smallest atom?
Is hydrogen or helium the smallest atom? My teacher said that the smallest atom is the helium atom, but I think that the smallest atom is the hydrogen atom. It has a single electron and a single ...
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Why is sulphur not written as S8 here [duplicate]
I learnt that sulfur dioxide and hydrogen sulphide react to form sulfur and water.
The reaction given was:
$\ce{SO2 + 2 H2S -> 2 H2O + 3S}$
So why is the product sulfur written as $\ce{S}$ and not ...
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What is "gram atom of an element"? [duplicate]
I've seen so many answers on Quora that got me lost :
1st answer :
The three are similar.
Gram atom.... Take the atomic mass of an element and express it in grams (sodium for example atomic mass is 22....
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The necessary energy required to ionize 1g of potasium in its fundamental state if the ionization energy is given
The energy of ionization of the potassium is $\pu{6.94\cdot 10^{-19} J/atom}.$ Find the necessary energy to ionize $\pu{1 g}$ of potasium that is found on its fundamental state.
Attempt. I really ...
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Comparing average radius of subshells for multielectron atoms
I recently came across a question comparing the average radius of subshells.
A search on the internet gave the following result for single electron atoms:
$$\langle r\rangle_{n,\,l}=\frac{a_0 n^2 \...
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How many atoms are there in single element? [closed]
Elements are chemical substances made up of the same types of atoms (atoms with the same proton number), whereas molecules are chemical compounds made up of atoms from two or more different elements.
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Why does increasing subshell cause ionization energy to decrease?
I know that increasing subshell decreases ionization energy; for example, going from Beryllium to Boron. I do not understand why this is.
The answer my textbook (Chemistry 2e on OpenStax) gives is ...
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respective posistion of d and p orbitals in a multielectronic species
we write the electronic configuration of atoms as [noble gas core]4s2 3d10.that is that due to energy considerations(aufbau principle) in multielectronic species.
what i want to know is whether the 4s ...
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Lother Mayer curve
While studying about atomic trends, I encountered the Lothar Meyer curve:
If the covalent radius decreases across a period, why is the graph of atomic volume reaching local minima halfway in the ...
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The ambiguity regarding aufbau principle
According to a Blog https://ericscerri.blogspot.com/2012/06/trouble-with-using-aufbau-to-find.html
written by Dr.Eric Scerri,
On moving from the $\ce{Sc^3+}$ ion to that of $\ce{Sc^2+}$ it is plain ...
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How to derive the number of spectral lines?
Recently, I found that when electrons in an atomic sample de-excite from a higher energy level ($n_2$) to a lower energy level ($n_1$), the number of spectral lines observed in the spectrum is
$$\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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