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.

Filter by
Sorted by
Tagged with
5
votes
2answers
1k views

Quantum mechanical model of atom and the quantum numbers

I studied Bohr's model of atom and then the drawbacks of it and then quantum mechanical model of atom. Now quantum model is according to uncertainty principal and dual nature of matter and it says we ...
5
votes
2answers
403 views

Energy of the n-th level for an atom

Going through the Bohr's model and his assumptions, I came across with this formula to find the energy of the n-th level of any atom: $$E = - \frac{Z k_e e^2}{2r_n} = -\frac{Z^2(k_e e^2)^2m_e}{2\...
5
votes
1answer
146 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 ...
5
votes
1answer
402 views

Is NaCl crystal always going to have even number of atoms?

I just read: In $\ce{NaCl}$, atoms don't aggregate so as to form discrete molecules but they are held together in a network structure. The ratio of the $\ce{Na}$ to $\ce{Cl}$ atoms in a sodium ...
5
votes
1answer
919 views

How were the absolute masses of atoms calculated before the mass spectrometers?

I understand that true (non-relative) masses of atoms are calculated with a mass spectrometer. using this relationship: Centripetal Force = Force due to magnetic field(B) But I was wondering how ...
5
votes
1answer
992 views

Are photons ejected from atomic nuclei?

I have heard that electrons absorb or eject photons when transitioning from one orbital to another. Is this correct? Can atomic nuclei eject photons?
5
votes
2answers
4k views

What defines an element's taste?

A useful post by @Martin indicated that probably the naming of Sweetwater town is because of the sweet tasting lead compounds in it's water. Then my question arose. I know that the taste of any ...
5
votes
1answer
1k views

Why Aren't Chlorides Of The Noble Gases As Prevalent As Their Fluorides?

I can't find the answer to this question on this SE website, and I apologize for the repetition if it has been answered before. It is my understanding that compound formation has only been observed ...
5
votes
1answer
5k views

What is the significance of Law of Multiple Proportions?

I cannot understand how the Law of Multiple Proportions is significant, or how does it further improve over Law of Conservation of Mass or Law of Definite Proportions. From Wikipedia: If two ...
5
votes
1answer
9k views

Sulfur trioxide - vacant d-orbitals

Sulfur trioxide violates the octet rule. Upon drawing the Lewis dot structure for sulfur trioxide, we see that the central sulfur atom is bonded to three other oxygen atoms by double covalent bonds. ...
5
votes
1answer
3k views

When is phosphorus a polyatomic molecule?

Phosphorus is listed as a single element in the periodic table; however, I see that it is also a polyatomic molecule as $\ce{P4}$. I am trying to determine the number of atoms of phosphorus in an ...
5
votes
2answers
1k views

What does it mean that an electron pair "spends more time" nearer an atom?

In a book I am reading, it is said In the $\ce{HCl}$ molecule, the shared pair of electrons spend more time nearer the chlorine atom. In the $\ce{HF}$ molecule, the shared electrons spend more time ...
5
votes
0answers
132 views

Terms related to the structure of atom [closed]

In my chemistry textbook, the chapter "Structure of Atom" deals with the old Bohr's model and the new Quantum mechanical model. But when I read the contents of the new model of atom, there were terms ...
5
votes
3answers
37k views

Why does ionization energy increase as we go from left to right in a period?

Why does ionization energy increase as we go from left to right in a period? In my textbook, the explanation is as follows: "This is consistent with the idea that electrons added in the same ...
4
votes
3answers
4k views

Why can't we use fusion to make ourselves rich?

As we know on fusing two hydrogen atoms we can convert it to helium and by breaking them we get two $\ce{H}$ atoms. So why can't we convert mercury to gold by removing 1 proton per atom?
4
votes
3answers
416 views

Does electron mass decrease when it changes its orbit?

I have studied this in my chapter atomic structure that when an electron changes its orbit from lower energy to higher energy state , it does not state in my book that it moves there but that it ...
4
votes
3answers
11k views

Is a single carbon atom stable?

It is well known that single atom of oxygen is not stable, and it forms $\ce{O2}$ molecule. But elements like carbon form a network of repeated bonds. As answered in another question, last atoms in ...
4
votes
3answers
2k views

What do atoms look like?

A professor of mine noted that when he was in school, microscopes weren't powerful enough to resolve certain things (I forgot what it was). But current microscopes are powerful enough. Extrapolating ...
4
votes
2answers
4k views

What is the physical state of a single atom?

Can a single atom on its own be either a solid, liquid, or a gas? Or is it none of them?
4
votes
1answer
880 views

electron passing nodes?

When one say that the electron goes from 1 orbit , say 2S, to another (higher) orbital, say 5P, it mean that the electron is excited to that orbit by some mean. In doing so it also it will also cross ...
4
votes
2answers
4k views

Atomic radii of Sc, Ti, Fe, and Co

The atomic radius of Sc is $\pu{162pm}$, Ti is $\pu{147pm}$, $\ce{Fe}$ is $\pu{126pm}$, and that of $\ce{Co}$ is $\pu{125pm}$. The electronic configuration of $\ce{Fe}$ is $\ce{[Ar] 3d^6 4s^2}$, and ...
4
votes
2answers
133 views

In Chemistry, is it possible to use the old representation of the atom as a nucleus surrounded by orbiting particles?

In Physics, Newton's laws are enough for many applications. Sometimes, relativity must be used instead or complementary, and sometimes, Quantum Mechanics. Is this the same case with Chemistry? Are ...
4
votes
2answers
13k views

Z* effective charge and Ionization Energy

I'm trying to figure out the patterns for Ionization Energies. I am familiar with the periodic trend, however things become quite different when we hit the 1st I.E. For example, Na has an I.E(1) of ...
4
votes
2answers
988 views

Spiralling of electrons into the nucleus

A drawback (and a major one) of Rutherford's model was that the electrons, being accelerated charged particles, would gradually spiral into the nucleus and collapse into it. My question is how did ...
4
votes
2answers
6k views

Why is Graphene So Strong?

There has been a lot of news about Graphene since its discovery in 2004. And as we are all told it is a revolutionary material which is very strong, conductive and transparent; even in some cases it ...
4
votes
2answers
2k 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 ...
4
votes
3answers
19k views

Is ionic bond just formed by "electrostatic" interaction between two oppositely charged ions?

According to the definition of ionic bond: An ionic bond is a type of chemical bond formed through an electrostatic attraction between two oppositely charged ions. If we consider the above ...
4
votes
3answers
1k views

Stability of Bohr Orbits

In class we had been taught that Rutherford's model was unsuccessful because it failed to show that the orbits are stable because the electrons would lose energy because of electromagnetic radiation. ...
4
votes
1answer
249 views

Base Peak Intensity different than higher value in Mass Intensity Map

I've been working with mass spectrum data analysis (but my field is computer science). I'm using a library that allows me to get the entire Mass Intensity of the MS1 scan (such as [time, intensity])....
4
votes
2answers
121 views

What is physically responsible for different compounds with the same types of atoms?

I only have a GCSE in Chemistry but I have discovered a lot of resources myself. One thing I cannot find an answer to is this: What is physically responsible for the different compounds you can get ...
4
votes
2answers
264k views

Is there an easy way to find number of valence electrons"

I want an high-school level answer. What I mean with "valence electrons" is the outermost electrons in that atoms' electronic arrangement? For example, 3 in an atom with an electronic arrangement of 2,...
4
votes
1answer
286 views

What were the expectations of Rutherford's gold foil experiment? [closed]

At the time when Rutherford's gold foil experiment was performed, Thomson's plum pudding model was believed to be true (at least by Rutherford himself and his students). With this model in mind ...
4
votes
1answer
656 views

Reasons for weakness of London dispersion force in graphite?

The layers of graphite are held together via London dispersion force. This force is weak. I know carbon having a smaller atomic radius and few electrons is one factor for this force's weakness. But, ...
4
votes
1answer
100 views

Can atomic number change the type of electromagnetic radiation being emitted when a electron drop from a energy level to another?

Without getting into too much/any math, I just wanna talk about intuitions if possible. If atomic increase, the attraction increase, and consequently the potential energy increase. More energy leads ...
4
votes
0answers
226 views

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 ...
4
votes
0answers
87 views

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}...
3
votes
2answers
2k 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^...
3
votes
2answers
29k views

Calculate the number of atoms of oxygen present in 1.3 mol of sulfuric acid

Calculate the number of atoms of oxygen present in $\pu{1.3 mol}$ of $\ce{H_2SO_4}$ 1 mol has $6.02\times 10^{23}$ atoms So $\pu{1.3 mol}$ must have $1.3 \times 6.02 \times 10^{23} = 7.826 \times 10^...
3
votes
2answers
702 views

Cause of continuous spectral lines [closed]

We know different types of atoms have different spectral lines. But what exactly are the spectral lines representing? What causes white light to have a continuous spectra while other atoms show ...
3
votes
1answer
4k views

Finding out the number of atoms in the sun.

This is the question from the text book: This is what I did, since it worked with all the previous questions (similar to this). $$ \frac{\frac{4}{3}\pi(7*10^8)^3*1.4}{1.008} * 6.022*10^{23} $$ ...
3
votes
2answers
991 views

What is the dimension of Avogadro's constant?

What is the dimension of Avogadro's constant ($N_\mathrm{A}$). On Wikipedia it says it is dimensionless, but in Nigel Wheatley's article (pdf) On the dimensionality of the Avogadro constant and the ...
3
votes
1answer
7k views

When was the amu renamed the dalton? [closed]

I taught chemistry for 30 years and never encountered the unit until I saw it on a juice bottle!
3
votes
3answers
2k views

Can the regions of 1s and 2s subshells overlap?

I was studying atomic orbitals and always had this question lingering. As we can see in the image, the 1s and 2s subshells both are known to closely surround nucleus. The overlapping peaks in the ...
3
votes
1answer
1k views

It is said that atoms cannot be created. If so, then how did atoms get created after the Big Bang? [closed]

I read somewhere that atoms cannot be created. If this is true, then how did the atoms form after the Big Bang? Also, does this mean that the number of atoms in our universe has remained the same ...
3
votes
1answer
4k views

What atom is always paramagnetic and why?

Regardless of its electron configuration, it must always be paramagnetic when it's a single, neutrally charged atom: (A) Carbon (B) Nitrogen (C) Oxygen (D) Neon (E) Argon At first, I eliminated D ...
3
votes
2answers
23k views

Ground state electron configuration of chromium [duplicate]

What is the ground state electron configuration of chromium? Is it $\ce{[Ar]}4s^23d^4$ or Is it $\ce{[Ar]}4s^13d^5$
3
votes
2answers
3k views

What is continuum in line spectra?

I read that continuum in line spectra is noticed beyond a certain limit. What does it mean?
3
votes
1answer
1k views

Why do ion cores not move in a metal?

The delocalized electrons in a metal move about because of the electrostatic attractions between them and many different positive ion cores. But why does the same not occur with the ion cores ...
3
votes
3answers
3k views

How do 1s and 2p orbitals overlap?

In the following figure we can see that the p-orbitals overlap 1s orbital (though relatively very little). How can an electron in p-orbital, be simultaneously in the 1s orbital at any given point ...
3
votes
2answers
106 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-...

1 2
3
4 5
10