Questions tagged [electrons]

Electrons are subatomic particles with the symbol e−. They have a negative electric charge (-1 elementary charge. )

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Confusion regarding 1st and 2nd electron gain enthalpy

$\ce{O}$ has the 1st electron gain enthalpy $\pu{-141 kJ mol-1}$. $-ve$ value implies that energy is released when electron is added to an isolated atom. This also means that if $\pu{141 kJ}$ energy ...
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Why is hydrated Lime Ca(OH)2 more reactive than standard quicklime CaO?

As the title suggests. I've been looking into geopolymer research papers and have seen that some people use Ca(OH)2 instead of CaO to achieve faster reaction rates but I'm not sure why and I can't ...
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If the charge of an atom's nucleus equals the total charge of its electrons, how can the nucleus attract more electrons, with what charge? [duplicate]

We know that atoms are neutral and this means that there is no extra positive or negative charge. All the charge of the atom's nucleus is used to attract all of its electrons and vice versa. So how ...
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What is the net gain of charge carriers in a semiconductor if an atom is removed?

In pure germanium, all Ge atoms are bonded with a tetrahedral geometry. It has a band gap and is a semiconductor. If we remove one Ge atom, what type(s) and how many charge carriers will be generated? ...
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Why is polystyrene (PS) an electrical insulator

The reason behind why graphite is electrically conductive is as ancient as the age of the Queen: that, electrons inside the benzene ring are delocalised. However, if one looks the repeating unit of ...
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How do the spin-matrices change in systems without spherical symmetry?

The (non-relativistic) spin matrices of a free electron, with $z$ as the quantization axis, read: $$ \boldsymbol{S}_{x}=\frac{\hbar}{2}\left[\begin{array}{ll} 0 & 1 \\ 1 & 0 \end{array}\right],...
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What is the paramagnetic susceptibility of sodium at around room temperature?

Proposed solution: This question comes from Tanner's manual Introduction to the Physics of Electrons in Solids, at the chapter dedicated to the application of the Fermi gas model. The Fermi energy is $...
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Shielding vs electron-electron repulsion

Example of shielding: (source) The last electron in the 6s subshell of $\ce {Cs}$ is shielded from the nucleus by the inner electrons. Example of electron-electron repulsion: The electron affinity of ...
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What happens during a displacement reaction? [closed]

When Zn metal is added to a solution of Cu(II)SO4, Zinc displaces Cu to form ZnSO4 as Zn is more reactive than Cu. What I don't understand is how. 1- What I'm assuming is: Zn metal collides with [SO4]...
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Observation of deflection in the Cathode ray experiment

In the Cathode Ray Experiment used to discover the electron, (This is what my textbook says (Grade 11) so if there's any additional parameters that I do not know of I apologize) The cathode ray tube ...
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A question regarding excitation of electrons in atomic orbital [closed]

In Bohr's model of an atom, the formula used to find the energy between the 2 orbits and wavelength of emitted photon was valid only for single electron species like hydrogen.In the case of a multi-...
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How to calculate ionization energy of an atom provided energy of the electron at ground state? [closed]

It is given that in ground state the energy of electron in hydrogen atom is $-2.18\times10^{-18}\mathrm{J}$. I'm required to calculate the Ionization Energy in kJ/mol Question for reference: At ...
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What will be easier reduced: ferric oxihydroxide or Fe(III)oxide?

related to the productivity potential of methanogenic bacteria in anaerobic conditions where iron oxides are present, is there a difference between ferric oxihydroxide and Fe(III)oxide regarding their ...
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1 answer
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Is an electron's charge arbitrarily called negative? [closed]

In Cosmos Carl Sagan writes Electrons are electrically charged, as their name suggests. The charge is arbitrarily called negative. Is this true (I know the book is out of date, like how Titan is ...
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Can an electron be excited to a spin state with s ≠ 1/2?

I used to think that all nuclei have fixed intrinsic value of the nuclear spin quantum number, $I$. For example, $\ce{^1H}$ must have a nuclear spin of $\frac{1}{2}$, $\ce{^{14}N}$ must have a nuclear ...
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How is MnS + 2HCl -> MnCl2 + H2S a redox reaction, in terms of electron transfer?

$$\ce{MnS + 2HCl -> MnCl2 + H2S}$$ If oxidation and reduction is taken to be the loss of hydrogen and the gain of hydrogen respectively, then I can see how the aforementioned reaction is redox — $\...
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AlCl3 and water

While reading Clayden's (et al) Organic Chemistry I stumbled upon a reaction on page 120 that I just fail to wrap my brain around. It describes a reaction of AlCl3 with water and states that, quote, &...
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How do you draw the pi MO diagram for the acetate ion CH3COO-

How do you draw the pi MO diagram for the acetate ion CH3COO- ? I get stuck with the number of electrons on the 2p orbital of Oxygen atom. My teacher said 1 oxygen has 1e, the other has 2e. But ...
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How do we write spin multiplicity for Mn(2+), Mn(7+)?

Mn has atomic number = 25 Since it is an exception to electronic configuration , unlike having = $\mathrm{3d^7}$ , it has electronic configuration = $\mathrm{3d^5,4s^2}$. Formula for spin multiplicity ...
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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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What will the correct value of spin quantum number for last electron of Na+ ion?

Electronic configuration of $Na^+$ ion is $1s^2,2s^2,2p^6,3s^0$. I have noticed usually , we take spin quantum number as +1/2 first & then -1/2. So , like for the above Q:It is for first 3e=+1/2 &...
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Why is the momentum operator imaginary?

I'm a beginner in quantum mechanics, and I'm pretty much confused with the momentum of electron in hydrogen atom. The wave function of the electron in 1s orbital of hydrogen atom is $\Psi_{1s} = \frac{...
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Why is the distribution of electrons of calcium in K,L,M,N shells 2,8,8,2 instead of 2,8,9,1?

I'm a beginner to this topic, so this would likely sound dumb. As far as I know, when distributing electrons in energy shells, the last energy shell can't have more than 8 electrons. So for calcium, ...
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1 answer
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Evidence that electrons don't exist between orbitals? [closed]

I don't understand the logical jump that was made early on in the atomic age, to conclude that electrons jump in and out of existence when moving between orbitals? Similarly, why do electrons need to ...
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20 votes
3 answers
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True or false: "A used AA battery contains fewer moles of electrons than a new AA battery."

I recently took a Gen. Chem. 2 exam that contained this question. I answered false, but my professor said the answer is true. My reasoning was that any electrons that leave the anode end up at the ...
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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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3 votes
3 answers
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How to Combine an Emission spectrum into a colour? [closed]

I am trying to wrap my head around the flame test, and for the most part, it is making sense. My question is their a way to figure out the colour of a flame of an unknown element given the emission ...
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Is there a molecule which has only lone pair electrons? [closed]

Lone pair electrons are "valence electrons that are not shared with another atom in a covalent bond" (Wikipedia). Is there a molecule which has only lone pair electrons?
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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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How to know the number of valence electrons of f-block elements? [closed]

I kinda know how to get the valence electrons for s/p/d- blocks but i don't know about the f-block. Wikipedia says that valence electrons for f-block is ns + (n-1)d + (n-2)f, so is it true? If so can ...
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Linearity of membrane resistance and contact resistance overvoltages in proton-exchange-membrane-water-elektrolyzer-cells (PEM-WE)

I am questioning why the cell component's resistance to the electrons (contact resistance) and protons (membrane resistance) flow follow the ohmic law. This assumption is made in recent papers on PEM-...
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Why electron configuration of thulium is $[\ce{Xe}]~\mathrm{(6s)^2(4f)^{13}}$ instead of$[\ce{Xe}]~\mathrm{(6s)^1(4f)^{14}}$?

We know that half-filled or full filled orbitals are more stable. That's why the ground state electron configuration of gadolinium is $[\ce{Xe}]~\mathrm{(6s)^2(4f)^7(5d)^1}$ rather than$[\ce{Xe}]~\...
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What does valence electron mean (in the context of spdf orbitals)?

For a little bit of context, my background is in physics and my understanding of chemistry doesn't go past, say, middle school level. Recently, I decided to self-study chemistry and picked up "...
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1 answer
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Can use lead(II) oxide instead of lead(IV) oxide in car battery?

Question: If the discharge input equation $\ce{PbO2}$ is replaced by $\ce{PbO}$, will the battery still work? I think the product will not be water anymore but hydrogen gas. I am asking this question ...
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2 votes
3 answers
2k views

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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1 answer
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Hydrated electrons produced by radiation vs electrons from electrostatic charge: are they equally reactive?

One of the species generated in water or aqueous solutions by the ionizing radiations are free electrons that quickly become "hydrated" or "aqueous electrons" (see for example this ...
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1 answer
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How does high voltage on the electrodes ionize a gas?

I was studying cathode ray experiment and there the electrons were obtained by ionisation of the gas inthe tube by the high voltage on the electrodes. So how does this happen?
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5 votes
1 answer
695 views

What would happen if electrons were spin-1?

We were speaking about this in class, but I can't understand it quite well. What would happen if (hypothetically of course) the allowed $m_s$ values were $-1$, $0$ and $1$? What impact does this have ...
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How big a role does electron repulsion play in regard to the bond length of a covalent bond? [duplicate]

In a covalent bond, there are several forces acting together to determine the bond length. Electron-electron repulsion increases the bond length. Proton-proton repulsion increases the bond length. ...
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1 answer
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Quantifying location and volume of "lone pairs" for VSEPR

Of course molecular shape and the VSEPR model come up frequently. As discussed previously in a valence bond picture like VSEPR, the lone pair electrons are closer to the atom than bonding pairs, and &...
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1 vote
0 answers
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How do dielectric molecules in a liquid phase align when polarized?

As seen in the diagram, when a dielectric material becomes electrically polarized, the molecules align themselves in a manner where the respective charges are parallel to each other horizontally. ...
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1 vote
1 answer
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When was the mass of hydrogen known?

During Robert Milikan's time, he uses the charge-to-mass ratio from J.J. Thomson's research of the electron (which is $1.759\cdot10^{11}\ \mathrm{C/kg}$) to calculate the mass of electron. Did he know ...
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4 votes
4 answers
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Can a metal be forced to form an anion theoretically? [duplicate]

I know that metals have the capability to lose electrons and form cations, but is it also theoretically possible to supply an electron to a metal so that it forms an anion? If so, has it ever been ...
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1 answer
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Order of Shielding Effect for orbitals

From what I know Shielding effect is the ability of inner electrons to repel outer electrons and reduce the Nuclear charge felt by the outer electrons and this is caused by electron-electron repulsion....
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5 votes
1 answer
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How can a hydrogen atom ever emit an X-ray photon?

From Scientific American, February 2014: The Proton Radius Puzzle: ...we had to tune the laser so that it came in with exactly the right amount of energy. The atom would make the jump to the higher ...
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2 votes
1 answer
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What is the average distance between electron 'shells' in an atom? Or between the innermost shell and the nucleus? [closed]

Somehow, I've never come across any mention of the actual, physical distances between, say the 1s and 2s shells in an atom, whether large or small.... I know that p, d and f (and g?) shells are oddly ...
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3 votes
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Why is the bond angle of sulphur difluoride greater than that of hydrogen sulphide?

Why is the bond angle of $\ce{SF_2 (98.05^\circ) > SH_2 (92.11^\circ)}$? Isn't this contradicting Bent's rule or otherwise electron repulsion rule ? Fluorine is more electronegative and hence it ...
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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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1 vote
1 answer
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Thickness of proton exchange membrane (Nafion)?

I am looking into using a proton exchange membrane for a bio-energy cell experiment. Previous scholars have been using Nafion as a PEM to place between the anode and cathode (air-cathode). the ...
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2 votes
2 answers
204 views

What does Bohr's model predict if the mass of an electron becomes 10 times its actual mass? [closed]

If the mass of an electron becomes 10 times its actual mass, which of the following statements is correct regarding Bohr's model: Velocity of electron increases by 10 times. Orbit radius decreases by ...
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