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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,...

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26 views

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?
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71 views

Confusion about electron arrangement in elements

My textbook says, "The first shell can hold only 2 electrons. The second and subsequent shells can hold 8 electrons to give a stable noble gas arrangement." Can someone explain me if it is MAXIMUM 8 ...
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31 views

Is it possible to determine the properties from a element based on the atomic structure [duplicate]

as the title already says i am trying to figure out if there is a way to determine the properties from the atomic structure of an element. So lets say we have the following water atom: the atomic ...
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24 views

How to use Hund third rule for cases like Nb, Ru, Rh, Pt?

How do I use Hund third rule to determine the value of $J$ for ground state for cases like Nb, Ru, Rh, Pt where there is 1 electron in s orbital and then an incomplete p orbital, and besides, S nor L ...
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2answers
3k views

Is there radioactivity at absolute zero? [closed]

Theoretically, will a radioactive material still be radioactive at absolute zero? What would happen at the lowest realistic temperatures we have ever achieved? Will radioactivity stop at absolute ...
2
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1answer
54 views

Understanding water models?

I generally work on fluid flow, so some basic concepts in chemistry are new to me. Work I'm doing requires use of molecular dynamics (MD) to do classical potential simulations of water–NaCl systems ...
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2answers
42 views

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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2answers
53 views

Question about the definition of an isotopes

My answer was as follows : atoms of the same element with differrnt relative atomic masses. However in the mark scheme the answer was simply : atoms of the same element with different masses. Was ...
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2answers
42 views

Can there be any substance whose number of electrons and protons are different at neutral state

I want to ask that if there any substance that has the different number of electrons and protons at its neutral state
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1answer
27 views

Atoms in Solar Cells

An electric field in solar cells is created through photons knocking electrons off of atoms. What happens to the positively charged atoms once the electrons have been knocked off? Furthermore, are the ...
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1answer
45 views

How are the molar mass and molecular mass of any compound numerically the same?

This observation is really annoying me, and the internet isn't providing me with any solid answers. Either their definitions of molar mass completely differ, or they don't stick to their own ...
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1answer
629 views

Hydrogen molecule potential energy graph

In the above graph, I was confused at the point where the internuclear distance increases and potential energy become zero. Though internuclear distance is very small and potential energy has ...
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2answers
65 views

Atomic weight = expected weight?

The atomic weight of an element, is it accurate to say that another way to think of it is the expected value of that element's weight if we were to sample one at random from the environment? Are man-...
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1answer
85 views

What is the true depiction of the periodic table?

Normally with the periodic table the lanthanide series is separated out because it's long and would make the table wide. I looked for an expanded version and found this: I found it kind of strange ...
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1answer
68 views

How did early chemists measure mass of atoms?

Here a book says that Berzelius measured atomic masses using a simple lab and his measurements was so close to modern results. Can someone explain how a person living in 19th century was able to ...
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2answers
140 views

Why do atoms have electron Affinity? [duplicate]

Atoms are stable so how can they pull electrons i.e how do they have any electron affinity at all?
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55 views

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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54 views

Rutherford's alpha particle scattering experiment for sheets made of different metals [closed]

The correct order of increasing number of alpha particles passing undeflected through the foils of Au, Ag, Cu and Al of 1000 atoms thickness each in an alpha scattering experiment of Rutherford would ...
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37 views

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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1answer
119 views

Trying to understand the contradiction in the data of Proust/Dalton/Berzelius vs Gay-Lussac

I am trying to understand some of the historical context behind the discovery of atoms (pre-Avogadro). In particular, I am getting stuck in reading the following documents: http://physics.unl.edu/~...
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3answers
151 views

Are ions actually charged particles?

For instance, if an atom loses an electron and becomes a cation, such as sodium, how does that make the sodium atom positively charged? The sodium's atomic radii decreases due to less electron-...
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1answer
61 views

Finding molecules that you randomly create using a modeling kit

I recently bought https://snatoms.com/ (which is just a real-life modeling kit for atoms/molecules) and was just keen on learning about chemistry in general. I often randomly join atoms to make up ...
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0answers
92 views

Quantum Mechanical Model of An Atom, Shells, Subshells [duplicate]

I've just been introduced to the quantum Mechanical Model of an Atom, so please bear with me on this one. Are Subshells and shell physical things, like do they really exist, or is it a concept only to ...
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2answers
879 views

What is the difference between ''1 C atom and 1 mole of C atoms?'' [closed]

Does 1 C atom mean 1 single C atom out of Avogadro's number of C atoms = 1 single C atom out of 6.023 X 10^23 numbers of C atoms? Does 1 mole of C atoms mean Avogadro's number of C atoms = 6.023 X 10^...
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1answer
42 views

What makes bond break apart from heat? [closed]

What makes bonds break apart from heat? I am wondering if anyone could explain the reasons why new bonds are formed in the absence of energy. I have found that they form in order to lower the overall ...
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0answers
26 views

How did the atomic number and atomic mass of elements discovered? [closed]

Elements are small for our naked eyes.so,how did the discovery of its atomic number and mass number took place?
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0answers
53 views

Why do objects gain electrons? [duplicate]

I have read that objects gain electrons to become negatively charged and also that they lose electrons to become positively charged. I have also read that same charges repel each other and non-same ...
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1answer
123 views

Atomic structure [closed]

We've got a homework and I know this question may seem so primitive, but I have already read whole textbook and I've been looking also on the Internet, but I still cannot find the right answer. I'd be ...
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1answer
34 views

How are ions formed? [closed]

I know that $\ce{H2O}$ is neutral. So how does adding one more hydrogen atom to it make it positive ion ($\ce{H3O+}$)?
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2answers
3k views

Why were elements discovered “out of order” after 1950?

I'm referring to the fact that there is one element that corresponds to one proton in an atom, a second that corresponds to two protons, up to, I believe, an element with 115 protons. These elements ...
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1answer
72 views

How isotopes atomic mass was defined?

So we say that 1 Amu (u) = 1/12 of the mass of a Carbon 12 atom. Im not sure about this, but I believe that first we measured the mass of 1 carbon 12 atom (This includes the mass defects that occur ...
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46 views

Huckel rule and the way atomic orbitals fill up

Huckel rule declares that a compound with 4n+2 electrons will be called aromatic where n takes 0 and positive integral values. If we see it that case when n=0,1,2,3...the number of elctrons is same ...
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2answers
151 views

Carbon tetraradical

I was just reading through Reactions: The private life of atoms by Peter Atkins and I noticed that in Chapter 3, the chapter on the combustion reaction, the author writes: As we watch we see $\ce {...
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0answers
34 views

Unable to understand properties of elements [duplicate]

Sorry about the daft question, but I can't understand this part of my chemistry book: It says the atomic size is decreasing (from sodium to argon), yet the atomic number goes: 11, 12, 13, 14, 15 ...
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56 views

Effective atomic number

Is there a database which contains the effective atomic number of some "popular" mixtures/compounds (e.g. BaSO4, PbWO4..)? And a comprehension question: Does it make sense to assign an element one ...
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2answers
125 views

Is atomic weight universal?

Are we advanced enough to calculate the abundance of an element throughout the universe or is our atomic weight only based on the occurrence of an element in our planet alone?
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2answers
128 views

A mole of atoms is the number of atoms whose total weight equals the atomic weight?

My textbook says, a mole of atoms is the number of atoms whose total weight = the atomic weight. There's something in the definition that's confusing me. Now what is confusing me is: Atomic weight =...
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1answer
30 views

Emission spectra [closed]

I am a highschool student and I am really confused about the following: We studied that electrons cannot be between main energy levels therefore in an emission spectrum of an element lets say hydrogen ...
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2answers
71 views

Atomic mass number and mass number in atomic symbol

In chemistry classes or even many different branches of chemistry textbooks, I am told that the atomic symbol $$\Large ^A_Z\ce{X}$$ includes the following notations: $A$ – "atomic mass" or "mass ...
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2answers
279 views

How many atoms are represented in this equation?

$\ce{Pb(NO3)2 + 2KI -> PbI2 + 2KNO3}$ The answer says 26, but shouldn't it be 13? Because actually, the number of atoms involved in the reaction are 13, and once the reaction is completed, again, ...
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1answer
87 views

What does “atoms make no compromises” mean?

I was watching The Ring of Truth - 5 Atoms and in the last part of the movie (the link starts at this part), Dr. Morrison said "When it comes to energy, atoms make no compromises. It is all or ...
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71 views

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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2answers
796 views

Is it possible to speed up radioactive decay? [closed]

I’m aware that elements like $\ce{^14C}$ have a known half-life, which means that over a span of roughly $5730$ years, half of the $\ce{^14C}$ atoms decay into $\ce{^14N}$. Are there any substances ...
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0answers
48 views

An elementary question worth asking [closed]

We all know that an atom starts moving faster when it's heated.But actually atom is not some new thing itself in the sense that it is just a bunch of electrons and protons. So, I think that same ...
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3answers
563 views

In helium-2, would each electron experience a single positive charge from the nucleus?

If we have an atom of hydrogen-1, we know that there exists one proton with one electron and in helium-2 two protons with two electrons. My question is that do protons get shared equally with ...
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3answers
290 views

Formation of Hydrogen - from a proton and an electron [closed]

If I place a proton and an electron close to each other, can they form an atom of hydrogen? Why or why not? Please explain the scenarios where this is not likely/unlikely. Personally I doubt it, ...
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1answer
125 views

Why doesn't velocity enter into Heisenberg's Uncertainty Principle?

So I came across Heisenberg's uncertainty principle in my 11th grade book, and I'm not convinced. It says $\Delta x \Delta p \gt \frac{h}{4\pi}$. Okay, but how does velocity even matter to determine ...
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1answer
901 views

Orbital diagram in which the Aufbau principle is violated [closed]

The orbital diagram in which the Aufbau principle is violated is: The answer given for this question is 3, but according to me if asked for Hund's rule violation then it would be 1, as electrons ...
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1answer
159 views

Are electrons in a helium atom diametrically opposite? [closed]

The helium atom is represented with electron opposite on same orbital: not fully opposite on same orbital and even on two normal orbitals: But in this case wouldn't the electron crash? Can you ...
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1answer
1k views

Calculating nearest neighbor distances

For cubic materials, there are equations in which to calculate nearest neighbor (NN), second nearest neighbor, etc. Can this be done with tetragonal crystal structures? I want to calculate NN, 2NN, ...