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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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 ...
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Inter electronic repulsion in s and d orbitals
This was written in a lecture slide:
Two electrons present in the same d-orbital repel each other more strongly than do two electrons in the same s-orbital.
Why is there a difference in the amount ...
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Difference between change in energy level and hyperfine energy level?
The second is the duration of 9 192 631 770 periods of the radiation
corresponding to the transition between the two hyperfine levels of the
ground state of the cesium 133 atom.
--> This ...
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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 $V_{x}...
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Ground state term symbol, why is $L = |M_L|$, if L must be a maximum?
I'm trying to understand how to predict ground state term symbol of atoms.
After finding the biggest S, why the biggest L will be $L = |M_L|$, where $M_L = \sum m_l$?
I know this rule works to ...
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How to derive the electron density of Hooke's atom?
Hooke's atom has the following wave function:
$$\Psi( \boldsymbol{r_1}, \boldsymbol{r_2}) \propto \left( 1 + \frac{|\boldsymbol{r_1} - \boldsymbol{r_2}|}{2} \right) \exp\left(-\frac{(r_1^2+r_2^2)}{4}\...
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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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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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As an atom get's bigger (on increasing atomic no.) , electrons have to move faster and faster around the nucleus, Why?
Does speed even make sense at such small scales ? Heisenbergs Uncertainty principle ?
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Comparision of the Ionisation Energy Change of the alkali metals and noble gases?
Currently I compare the ionisation energys of the alkali metals:
Li: $\pu{0.52 eV}$
Na: $\pu{0.50 eV}$
K: $\pu{0.42 eV}$
Where only a slight drop (appr. remain constant) occurs.
This ionisation ...
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Is Effective Nuclear Charge the same as Core Electrons?
I'm wondering, what is the difference between the two?
Using the equation for Eff: $\ce{Zeff = Z - S}$
Z being the number of protons in the nucleus and S being inner-shell electrons.
For example:
...
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How to determine the permissible values for which solution of the Schrödinger's wave equation exists?
My textbook( A Textbook of Physical Chemistry, Dr. O.P. Tandon ) says that solution of the Schrödinger's wave equation exists only for certain permissible values which are called eigen values.( ...
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Why are Bohr's formulae for radius and velocity still in use when Heisenberg's uncertainty principle predicts otherwise?
I learnt about Heisenberg's Uncertainty principle which states that it is not possible to determine the position and momentum of a small particle at the same time.
I was told that it is because in ...
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Few basic questions about ionic bonding and batteries (lead)
I've got a few very very basic questions about ionic bonds and their role in batteries.
My assumptions (correct me if I'm wrong):
Ionic bonds occur between a metal and a non-metal (the non-metal ...
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2
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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 ...
- 2,307
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First ionization energy of hydrogen molecule
If we have the dissociation's energies of hydrogen molecule $\ce{H_{2}}$($D_{0}$) and the corresponding molecule ion $\ce{H_{2}^{+}}$ ($D_{1}$) together with the first energy of ionization of hydrogen ...
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Magnetic moment of coordination complexes?
To understand the commonly quoted magnetic values of coordination complexes (central ion) we use
$$m_l=\sqrt{n(n+2)} \text{BM where BM}=\frac{e\hbar}{2m_e}\text{JT}^{-1}$$
$n$=number of unpaired ...
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1
answer
404
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Spin quantum number of electron
Why is the spin quantum number of an electron +1\2 or -1\2 in an atom? Is this an experimental value or theoretical value?
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3
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Comparing Succesive Ionisation Energies
I am trying to understand successive ionisation energies. In particular, an explanation for why the second ionisation energy is greater than the first ionisation energy. I'm looking for a clear and ...
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Why are electrons filled in fourth shell before the third shell is filled?
I am a beginner and am learning about atomic structure and I am getting confusions regarding the aufbau principle.
It is said that the electrons will be filled first in lowest available energy level. ...
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Does the electron in a neutral hydrogen atom ever exist in the p, d or f sublevels?
I learned that the electron in a neutral hydrogen atom can be excited to higher levels. But there are different sublevels in the levels. For example s, p, d and f.
Does the electron only jump from s ...
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Why hydrogen gas tube produce hydrogen atomic spectrum
To measure the atomic hydrogen spectrum people often uses hydrogen gas tubes as light source.
Since the gas in the tube is the molecule $H_2$ , why we obtain the spectrum of atomic hydrogen?
My guess ...
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What is the empirical formula of a compound where the mass ratio of sulphur and oxygen is 2:3?
This is how I tried to solve it:
$$\frac{2}{3} = \frac{0.67}{1}$$
$$\frac{32.06}{16} = \frac{2.00}{1}$$
$$\frac{0.66}{2.00} = \frac{0.33}{1}$$
I assumed by the result that if for every $\pu{1g}$ ...
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0
answers
262
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How can the potential energy at the infinite energy level in an atom be zero?
I have recently learnt about atomic structure and the Bohr model of the atom and have observed a discrepancy between it and my previous knowledge based on physics.
For simplicity, assume the atom is ...
user62318
1
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0
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556
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How does symmetry of half filled and fully filled orbitals lead to stability
I googled a lot about why symmetry of half filled and fully filled orbitals decreases their energy but every time it is repeated that symmetry leads to stability. So the question is why symmetry leads ...
1
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0
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398
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Understanding three-dimensional structure of common salt
I started reading through The Feynman Lectures and came across this diagram. What do the numbers next to the nodes in the diagram represent? It's not explained in the text. All that is mentioned is: "...
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Why are Alkali Metal Ions Soluble?
I think the question needs no elaboration. Why are salts containing Group 1A cations extremely soluble in water?
I speculate that the reason involves the low charge density of those ions in a given ...
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Use of statistics in this field
I am currently pursuing a statistics course and I an interested in knowing how can statistics help this field in future. (I am interested because I love chemistry very much) Specifically, are there ...
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Experimental Validation of Schrodinger's Electron Cloud theory
I am currently doing a report for school on the electron cloud atomic structure theory. One of the major points on my report is the experiments performed by the scientists (Schrodinger and Heisenberg) ...
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How would I find an apporpriate dopant element for a lattice
I am trying to figure how would I go about finding a dopant element that would fit in a copper lattice? I already have the data for the atomic dimensions and structure (available below), however how ...
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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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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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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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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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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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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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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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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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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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What is the general or ideal equation for the radial wave function?
I came across this question on the internet:
What is the value of $(n + l + r)$ in a given wave function, where $n =$ principle quantum number and $l =$ azimuthal quantum number and $r =$ total ...
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Is neutron a compressed form of hydrogen atom?
As I know:
$E_\mathrm{p} = \pu{938.272 MeV}, \quad
E_\mathrm{e} = \pu{0.511 MeV}, \quad
E_\mathrm{n} = \pu{939.565 MeV}$
$E_\mathrm{n} − (E_\mathrm{p} + E_\mathrm{e}) = \pu{0.782 MeV}$
$M_\...
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Why does q/m ratio(specific charge) depend on nature of gas in anode ray experiment?
I can't understand why $q/m$ ratio changes in anode ray experiment (discharge tube experiment) (which was carried out by Goldstein) with change in nature of gas?
Since $q=1.6\times10^{-19}\ \mathrm C$...
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Table of expanded electronic structures of atoms
Where can I find the table containing expanded electronic configurations for atoms in the periodic table, showing how outer electrons are distributed between different atomic orbitals?
I really just ...
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1
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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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Is the maximum oxidation state of an element equal to it's valency?
I know maximum oxidation state has a sign and valeny doesn't.... But, if we remove the sign then, would it be equal to the valency of an element? I earlier assumed that valency was equal to the ...
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If an atom of any element gained energy, does it always mean that its electrons gain energy too?
My book says ;
"The transitioning of electrons in atoms from one energy level to another is associated with changes in the energy of the atom."
But it hasn't made it clear whether or not the gaining ...
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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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Does berylium gain or lose electrons?
Does beryllium want to gain or lose electrons? I know it has 4 protons, 2 valence electrons, and it will gain or lose 2 electrons, but what is it?
