# 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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### Calculating the threshold frequency and kinetic energy of emitted electrons [closed]

I was working on the following problem: The work function of sodium is $\pu{2,5 eV}$. We illuminate it with a radiation that has a wavelength of $\lambda = \pu{2.0E-7 m}$. What is the threshold ...
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### Photoelectric effect problem: what is maximum wavelength for the photoelectric effect to happen? [closed]

I was working on the following problem, Find the kinetic energy of an electron removed from the surface of a certain metal by a radiation of frequency $\lambda =5\times10^{15}\; Hz$, if the ...
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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 ...
49 views

### 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 ...
41 views

### 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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1 vote
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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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### 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 ...
338 views

### 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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325 views

### 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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1 vote
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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 ...
1 vote
125 views

### 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 ...
445 views

### 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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1 vote
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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 ...
464 views

### 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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1 vote