Questions tagged [atomic-structure]

For questions about the various atomic structure theories, including the Bohr theory. Not to be confused with the actual arrangement of atoms in macroscopic solids ([solid-state-chemistry]) or newer quantum concepts ([quantum-chemistry])

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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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Problem with Potential Energy in Bohr's Atomic model [closed]

Question: What is the relation between potential energy ($E_\text{pot}$) and $\frac1n$ according to Bohr's model? ($n$ is shell number/principal quantum number) My Approach: Total energy = $E_\text{...
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1answer
62 views

Is the given statement regarding Radial Probability Distribution Function correct or not?

Radial Distribution Function $(4πr^2R^2(r))$ gives the probability of the electron being present at a distance $r$ from the nucleus. Answer: The given statement is correct. My Query: According to me, ...
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Question relating to Bohr's Atomic Model [closed]

Question: According to Bohr's atomic model, is the following graph correct? Answer: Yes, it is correct. My Approach: According to Bohr's Model, the total energy of an electron in the $n^{th}$ shell ...
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How many electron clouds are in an atomic orbital? [duplicate]

If an atomic orbital consisted of 2 electrons (its maximum capacity), how many electron clouds would there be? I think its 2 electron clouds, one for each electron but I'd love some confirmation.
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1answer
35 views

Atomic shielding 2s to 1s

How much is the effecting shielding of the 1s electrons from the 2s electrons? . Because the 2s subshell overlaps with the 1s subshell this will cause the 1s electrons to 'feel' less charge than the ...
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Why does the oxides that form change down the alkali metals? [duplicate]

Why does Li2O primarily form when Li has reacted with O2 but the Na2O2 forms for sodium? Moreover, the primary product for the other alkali metals are superoxides instead of oxides and peroxides. How ...
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3answers
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$\psi$ Represents amplitude of electron wave and $\psi^2$ represents electron density in a given space. How?

The $\psi$ represents amplitude of electron wave. So it's dimension should be $\left[L\right] $. But $\psi^2$ represents density of electrons in a given space. So it's dimension should be $\left[ML^{-...
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47 views

The true shape of p orbitals

I'm trying to model $\mathrm{p}$ orbitals using a 3D program. What confuses me is that there are 2 shapes of $\mathrm{p}$ orbitals. I'm not sure which one is the accurate model. And what is the ...
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1answer
49 views

absorption spectrum of hydrogen atom [closed]

In absorption spectrum of hydrogen atom, only one electron is present in its one atom which is in ground state, so it means that all electrons can only absorb energy of photon of wavelength which lies ...
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2answers
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Why is atomic orbital one electron wave function? Why distance from centre is proportional to angular wave function?

Consider the following statements: An atomic orbital is one electron wave function $\psi(r,\theta,\varphi)$ obtained from the solution to the Schrödinger equation. There two electrons in an atomic ...
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Magnetic moment of trivalent lanthanide cations

The effective magnetic moment $\mu_{\mathrm{eff}}$ of tripositive rare earth elements, is calculated by $$\mu_{\mathrm{eff}}=g_J\sqrt{J(J+1)}\mu_\mathrm{B}$$ Why can't we use normal formula as $\sqrt{...
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Notation in atomic structure

In the book, The theory of atomic structure and spectra, Robert D. Cowan says that the allowed terms of $p^2$ are $^1S$, $^1D$, $^3P$ and so the possible terms of $p^2 + p\quad$ (obtained by using the ...
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1answer
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How value of energy of elecron becomes more negative and radius of orbit decreases with increase in the value of atomic number? [closed]

I know how energy of elecron and radius of orbit depends upon principal quantum number......But how it depends upon atomic number?
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1answer
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Angular Momentum of an orbital and orbit [closed]

While pursuing forth in Atomic Structure, I encountered the following concepts... According to Bohr, the angular momentum of an orbit remains quantized, i.e $\displaystyle mvr = n\hbar .$ But he ...
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1answer
51 views

What element did Rutherford use to obtain alpha particles in his experiment of gold foil? [closed]

What element did Rutherford use to obtain alpha particles in his experiment of gold foil?
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1answer
30 views

Conversion factor for chemical to physical scale of atomic masses

Before the 1960s chemists and physicists used to have different atomic mass tables. The main difference was that the physicists assigned the $^{16}$O as the O=16 from mass spectrometry. Chemists on ...
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Why does exchange integral 1s2p not vanish for Helium excited state?

I am studying first-order perturbation theory applied to the first excited state of Helium. I am facing the following problem: I understand that the Coulomb integral for all 2p functions will not be $...
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1answer
56 views

True muonium energy levels [closed]

In a true muniom(muon-antimuon atom) do the energy levels match with that of the hydrogen's? The core is lighter for about 100 times but the muon is 100 times heavier than the electron so it would ...
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49 views

Term symbols for excited nitrogen (2s2p^4 configuration)

Looking at the NIST levels listing for neutral nitrogen atom, one of the excited configuration is $2s2p^4$ configuration. https://physics.nist.gov/cgi-bin/ASD/energy1.pl?encodedlist=XXT2&de=0&...
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1answer
28 views

Can you determine when the orbtials of an atom will hybridize?

We know that when it comes to C its orbitals hybridize (they become sp3 , sp2 or sp) and the energy levels of an hybridized orbital of this kind is lower than that of the p orbital that formed it but ...
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Why does ψ^2 ( square of orbital wave function ψ) give the probability of an electron in a given region? [duplicate]

Today I was introduced to the Orbital Wave Function for electrons. $\Psi$ is a mathematical function for coordinate of electrons and has no physical meaning. But $\Psi^2$ gives probability of an ...
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136 views

What is d-orbital collapse?

When I was perusing the works of Schwarz on atomic structure, I came across the unfamiliar term of d-orbital collapse. He describes it as a variation in energetic sequence from group 1 to 3 elements ...
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1answer
353 views

Electron pairing in atoms

A question asks: This question refers to isolated gaseous atoms. In which atom are all electrons paired? Ba, Br, S or Si? I thought it was Ba as its electron configuration is [Xe] 6s2. However, ...
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Does it exist a transgression to Hund's rule of maximum multiplicity principle in this given electron box notation?

The following question arises from a set of statements from which I'm asked to state whether they are true or false. This is as follows: Indicate which of the following statements are true or ...
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2answers
121 views

Effective nuclear charge and electron repulsion

To the best of my knowledge, the effective nuclear charge $Z_\mathrm{eff}$ is usually defined such that the potential energy of an electron in an atom, $\langle V \rangle$, can be expressed as $$\...
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Why is there a big jump in first ionisation energy between sodium and potassium?

I know the trend in group 1 is that ionisation energy decreases down the group due to an increase in atomic radius and more energy levels are added so more shielding, but I'm not sure why there's such ...
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1answer
249 views

What is more stable, Na+ or Na? [closed]

As per noble gas configuration $\ce{Na+}$ should be more stable than $\ce{Na}$. But at the same time $\ce{Na+}$ has a positive charge so it will be easily attracted by negative charge while $\ce{Na}$ ...
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1answer
156 views

Atomic Orbital and Wave Function

I was reading about the atomic orbital in my chemistry textbook. It says that the atomic orbital (psi) is a mathematical wave function that depends on the coordinates of the electron. It is also ...
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1answer
242 views

Empirical Evidence and Assignment of Orbital Energies (Electron Filling)

I see a lot of questions on electron configurations from students at various levels here. Students mechanically remember how to fill orbitals and sorry to say many teachers do the same. Not a single ...
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1answer
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Size of atomic shells

Is the distance of some $n^{th}$ shell ($n$ $\neq$ outermost shell) from the nucleus of an atom different for different elements? If so, then how much is the difference or how could we calculate it?
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Why $ns^2np^6$configuration so stable? [duplicate]

In my chemistry textbook it is said that noble gases have stable configuration because they have achieved the maximum outermost shell configuration, which corresponds to the $ns^2np^6$ configuration. ...
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2answers
246 views

Why is atomic number unique? [closed]

We all know that atomic number of an atom is "unique" just like fingerprint. And no two elements can have same atomic number. But how can we be So sure that no two elements can have same atomic number?...
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1answer
198 views

Diamagnetic vs Paramagnetic

As far as I know, to know whether a substance is paramagnetic or diamagnetic, we check if that particular species has got unpaired electron or not. But my textbook lists- Examples of Diamagnetic ...
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3answers
315 views

Photoelectric effect (AP Chemistry question)

Which of the following postulates regarding the photoelectric effect is considered to be INCORRECT according to the quantum mechanical model we currently understand? (A) Increasing the intensity of ...
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1answer
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Bohr's postulate of quantisation of angular momentum

The Bohr's postulate of quantisation of angular momentum can be written in a formula as $mvr = nh/(2π)$ where $m$ is mass of electron $v$ is its velocity $r$ is the radius of that shell $h$ is ...
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1answer
187 views

To move one electron in one H atom from the ground state to the second excited state, 12.084 eV are needed

How much energy is needed to cause 1 mole of H atoms to undergo this transition Assume Bohr's model of quantisation The energy for transition is $$1312\left(\frac{1}{n_1^2}-\frac{1}{n_2^2}\right)$$ ...
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Terminology of atomic spectroscopy: Difference Among Term, States and Level

In A Primer on Quantum Numbers and Spectroscopic Notation Contents, the concept of a term and level is described as a) The level is the set of 2J+1 states with specific values of L, S, and J. ...
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1answer
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Do different oxidation states of the same element have the same emission spectrum?

I looked at the flames of copper (I) chloride and of copper (II) chloride through a spectroscope and they looked the same. The flame colour is the same too. But since they have different oxidation ...
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1answer
128 views

Molecular dynamics (Mac OSX user): what software can I use to plot RDFs for NPT simulations? VMD only works for NVT (constant volume)

I would be very grateful if someone could recommend a way to plot RDFs for NPT ensemble molecular dynamics simulation results. I use CP2K to run NVT simulations and usually use VMD to process ...
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1answer
179 views

Who came up with the box and arrow diagrams for electron configurations?

In general chemistry texts, the electron configurations are sometimes shown in boxes with up and down arrows to show the concept of paired spins. My impression for years was that Hund used such ...
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Ratio of Total energy to Kinetic energy in hydrogen atom when the reference is changed

If in the hydrogen atom Potential Energy at $\infty$ is chosen to be $13.6$eV then the ratio of total energy and kinetic energy (with the sign) for $1$st Bohr Orbit is? My Attempt I just simply gave ...
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1answer
81 views

Doubt in a question related to electronic transitions in Bohr's orbits

Question In Bohr series of lines of hydrogen spectrum, the third line from the red end corresponds to which one of the following inner-orbit jumps of the electron for Bohr orbits in an atom of ...
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1answer
57 views

Why potential energy is neglected in this problem for calculating the energy difference between two stationary Bohr Orbits? [closed]

Question An electron in a hydrogen like atom makes a transition from a state in which its de-Broglie wavelength is $\lambda_1$ to a state in which its de-Broglie wavelength is $\lambda_2$, then ...
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1answer
109 views

How did Thomson calculate the momentum of electron when he didn't know the mass of electron?

This was proven in 1903 by J. J. Thomson who calculated that the momentum of the electrons hitting the paddle wheel would only be sufficient to turn the wheel one revolution per minute. source J. J. ...
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Are Slater’s rule and lanthanide contraction contradictory?

According to most textbook and the Wikipedia page of lanthanide contraction, the phenomenon is due to poor shielding of nuclear charge by 4f electrons. However, the σ value of 4f electrons to 6s is 1....
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1answer
250 views

Why does zinc sulfide glow when hit by electrons? [duplicate]

In cathode ray tube experiment in order to check the direction of flow of electrons a hole was made in a note and behind it phosphorescent material zinc sulfide it was coated. Why does zinc sulfide ...
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What will happen if electron as a wave undergo destructive interference while travelling in its Orbit?

Today I came across a justification of Bohr's angular momentum quantization using the De- Broglie's hypothesis. The justification said that since the electrons are having wave nature also then while ...
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Finding atomic number given energies of emitted photons

A hydrogen-like atom (atomic number $Z$) is in a higher excited state of quantum number $n$. This excited atom can make a transition to the first excited state by successively emitting two photons of ...