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
-3
votes
0answers
39 views

What is the term used when proton is different from similar atom? What about neutron and electron? [closed]

Can a proton be different from similar atoms? If so what is the term used for it? What about neutron and electron?
-5
votes
0answers
24 views

Number of moles of atoms [closed]

Does anyone know how to solve this question: "How many moles of atoms make up 2.3 mol of lead(ll) nitrate?" I'm not sure what it means by "moles of atoms" since the question ...
1
vote
0answers
35 views

Does the electron in a neutral hydrogen atom ever exist in the p, d or f sublevels?

I learned that the electron in a neutral hydrogen atom can be excited to higher levels. But there are different sublevels in the levels. For example s, p, d and f. Does the electron only jump from s ...
13
votes
3answers
469 views

Why do electrons jump back after absorbing energy and moving to a higher energy level?

Electrons in a shell absorb energy and move to higher energy levels, but they release their energy and jump back to the shell they originally were in. Why do they jump back? Why can they not keep ...
1
vote
0answers
41 views

Why ionic radius of H- is so large

The order of ionic radii for halogens: $$\ce{F- < Cl- < Br- < H- < I-}$$ What is the reason for such large ionic radius of hydride ion?
1
vote
1answer
80 views

What does orbital mean, exactly? [duplicate]

My teacher told me that orbital is the probability distribution data of the electron around nucleus which is amplitude data in a way. An example of how my teacher actually told what it means involves ...
1
vote
1answer
50 views

Why is the atomic mass unit less than the mass of both a neutron and a proton? [duplicate]

The atomic mass unit is $1.6605 \times 10^{-27}$ kg. This is less than the mean of the masses of 6 protons and 6 neutrons. How do we account for the lower mass ? My understanding is that some of the ...
7
votes
3answers
324 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 ...
1
vote
0answers
54 views

Is it true that one atom does not form a molecule? [closed]

Here it states that one atom can form a molecule. Notice here that , one N and one O atoms are related
1
vote
2answers
70 views

How is this possible in mole concept? [closed]

L = $6.022*10^{23}$ If I have one atom of oxygen , it has exactly L value. Now 2 atoms of a oxygen have 2L value.(Note that I mean 2O and not $O_2$here) Well , if we take a molecule made up of 2atoms ...
2
votes
1answer
77 views

What does Pauli’s exclusion principle mean in atomic or fundamental way? [closed]

It means is that no electron can have same n , l and $m_l$ but can have two different spin quantum number. I want to know why is this rule valid?Means there must be some other things happening also ...
0
votes
1answer
61 views

Is this diagram correct for difference between 2N and N2

There is 1 $\ce{N2}$ molecule formed with 2 atoms of nitrogen. 2N is 2 separate nitrogen atoms which have not formed any bond.Reasons could be that they didn’t get enough energy to form bond so they ...
2
votes
1answer
58 views

Why do Rydberg atoms have electrons that can transition above the first ionization energy?

Why do Rydberg atoms have electrons that can transition above the first ionization energy? This can only happen in a multi-electron system but I don't see how the Rydberg formula would even work for n ...
0
votes
0answers
21 views

Why hydrogen gas tube produce hydrogen atomic spectrum

To measure the atomic hydrogen spectrum people often uses hydrogen gas tubes as light source. Since the gas in the tube is the molecule $H_2$ , why we obtain the spectrum of atomic hydrogen? My guess ...
1
vote
1answer
60 views

Why does matter have spaces between them? [closed]

If you mix sugar Crystal in a glass of water and mix it well, the level of water will not rise.The reason they say is that matter have spaces between them.If matter have spaces between them , How ...
-2
votes
1answer
62 views

“Isotopes” in a molecule?

I just learned that atoms of the same element can have different mass because of they are isotopes. If there are two isotopes in which each reacts to form the same thing. Would the mass differ in each ...
-2
votes
1answer
26 views

Hydrogen and Hydrogen ion

Is it correct that a hydrogen atom only has 1 electron and 1 proton since the atomic mass is 1? Also, is the hydrogen ion composed of a single proton and no electrons? In an ionization process we know ...
0
votes
0answers
29 views

Reason for needing multiple radii for the same atom [duplicate]

Why do we need different types of atomic radii? Why can't there be just one radii for an atom?
0
votes
1answer
67 views

In metallic bonding, what causes a metal to lose its outer electrons and become an ion? [duplicate]

In metallic bonding, what causes a metal to lose its outer electrons and become an ion? I am trying to understand metallic bonding, atoms and ions.
2
votes
1answer
48 views

Why does covalent bonding not break down if observer effect can be applied to atomic electrons? [closed]

The observer effect in quantum mechanics states that when unobserved, quantum particles such as electrons can simultaneously occupy two different states. In an atom of any element, where there are ...
-2
votes
3answers
139 views

Does the 4s orbital really have a higher energy level compared to 3d? [duplicate]

For writing the electronic configuration of the $\ce{Fe^2+}$ ion, you need to remove two electrons (as it is an ion) which are from the highest energy level. Apparently, this would be $\mathrm{4s}$ ...
0
votes
1answer
29 views

Could observer effect cause electrons in one orbital to be found in another?

The observer effect states that when unobserved, absolutely small particles like electrons can simultaneously be in two different states at the same time. (Tro, N. J. (2015). Principles of Chemistry: ...
0
votes
2answers
83 views

Rules to follow while writing a chemical formula for polyatomic ions

In Science, textbook for class IX, chapter $3$ [1,p.38], it states: The rules that you have to follow while writing a chemical formula are as follows: in compounds formed with polyatomic ions, the ...
2
votes
0answers
68 views

Illustrating moles with sand grains, Are there more moles of SiO2 in a grain than moles of sand on the earth

I have been trying to understand the scale of atoms, thinking about sand grains as an example. With approximately $7.5\times10^{18}$ grains of sand on the earth that is $1.25\times10^{-5}$ moles of ...
14
votes
1answer
469 views

How did Mendeleev know elements from compounds or mixtures?

I read that Mendeleev initially thought didymium was an element, but it was actually a mixture. How did he know the rest of the chemicals in the periodic table were elements and not compounds, ...
0
votes
2answers
108 views

Confusion with definitions of mass [duplicate]

What is the difference between: atomic mass relative atomic weight relative isotopic weight standard atomic weight atomic weight relative atomic mass I am told by Wikipedia that: relative atomic ...
3
votes
2answers
283 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
102 views

While calculating the effective nuclear charge, why don't we consider effect of outer electrons on inner ones? [duplicate]

When calculating the effective nuclear charge for an electron, why do we only consider the repulsive effect of the inner electrons on the outer electrons? The outer electrons also repel the inner ones ...
3
votes
1answer
145 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 ...
0
votes
1answer
37 views

How do orbitals overlap in difluorosilane? [closed]

In $\ce{SiH2F2}$ four orbitals of silicon $(\mathrm{3s},$ $\mathrm{3p}_x,$ $\mathrm{3p}_y,$ $\mathrm{3p}_z)$ overlap with two hydrogen $(\mathrm{1s})$ and two fluorine $(\mathrm{2p}).$ I want to know ...
0
votes
2answers
120 views

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, ...
0
votes
1answer
228 views

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 ...
2
votes
1answer
306 views

Trend in atomic volume across a period [closed]

"Atomic volume decreases along a period, reaches a minimum at the middle, and then increases for the rest of the period" Why does the atomic volume, along a period, initially decrease, ...
1
vote
0answers
61 views

Why doesn't core charge increase down a group? [closed]

Atomic radius increases down a group because the electrons feel a lesser attraction to the positive nucleus (due to shielding from inner shells). Why then, doesn't core charge decrease seeing as core ...
-1
votes
1answer
48 views

Atoms and their vibration [closed]

We all know that the atoms in any solid matter vibrate about their mean position but why do they do so?? What will happen if they stop vibrating??
-2
votes
1answer
26 views

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?
8
votes
1answer
285 views

Ground state term symbol for Cerium (Ce)

I need to calculate the term symbol of the ground state configuration of Cerium. The electron configuration is: $[Xe] 4f^1 5d^1 6s^2$ Since the d and f electrons are in different subshelles, they are ...
2
votes
1answer
57 views

Why is the amu of chlorine-35 less than 35? [duplicate]

My book says that a proton weighs 1.0073u, a neutron weighs 1.0087u, and an electron weighs 0.00055u. Now, why is the mass of chlorine-35 equal to 34.969? Are there not 17 protons, 18 neutrons, and ...
0
votes
0answers
29 views

The meaning of magnetic quantum numbers' values

The $\mathrm{m_l}$ values in quantum mechanics, $1, 0, -1$ for p orbitals for example, do they refer to specific orbitals? Like, does $\mathrm{m_l} = 1$ refer specifically to $\mathrm{p_x, m_l} = 0$ ...
3
votes
1answer
71 views

Does direction matter in breaking a bond?

Im not sure if this question belongs here or in another community. I was wondering if the direction that we apply a force in order to break a bond matters and how it affects strength. Say we have one ...
0
votes
0answers
22 views

What is the general or ideal equation for the radial wave function?

I came across this question on the internet: What is the value of $(n + l + r)$ in a given wave function, where $n =$ principle quantum number and $l =$ azimuthal quantum number and $r =$ total ...
1
vote
2answers
142 views

Why we need the average atomic mass? [closed]

I know , Average Atomic Mass of an element is - the sum of the Masses of its isotopes,each multiplied by its Relative Abundance percentage (in decimal notation). But what confusing me is, what is ...
1
vote
0answers
47 views

What is the empirical formula of a compound where the mass ratio of sulphur and oxygen is 2:3?

This is how I tried to solve it: $$\frac{2}{3} = \frac{0.67}{1}$$ $$\frac{32.06}{16} = \frac{2.00}{1}$$ $$\frac{0.66}{2.00} = \frac{0.33}{1}$$ I assumed by the result that if for every $\pu{1g}$ ...
-3
votes
1answer
266 views

Why are moles of compounds have only 6.022x10 23 atoms? [closed]

I am a bit stuck on a basic chemistry concept. I understand that the Avogadro number indicates the number of chemical entities it has (ion, molecule or atom) What I don't understand is that when you ...
-4
votes
1answer
35 views

What would happen if we supercool and then superheat an atom very abruptly? [closed]

Now scientists have found ways to cool atoms to temperatures far lower than we ever could before and maintain them for longer, but what if we had one of those particles and then heated it as fast we ...
1
vote
1answer
416 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 ...
1
vote
1answer
91 views

Atomic emission spectrum assumption n_f = 3

It's a standard question on the atomic emission spectrum. An atomic emission spectrum of hydrogen shows three wavelengths: 1875 nm, 1282 nm, and 1093 nm. Assign this wavelengths to transitions in ...
3
votes
0answers
199 views

Ground state term symbol, why is $L = |M_L|$, if L must be a maximum?

I'm trying to understand how to predict ground state term symbol of atoms. After finding the biggest S, why the biggest L will be $L = |M_L|$, where $M_L = \sum m_l$? I know this rule works to ...
1
vote
0answers
42 views

Force on an electron in a given orbital [closed]

I was wondering whether there is any quantum mechanical equation to describe the force on a given electron in a given orbital of an atom (lets say, for the simplest case, for hydrogen atom). Also if ...
-6
votes
2answers
340 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?...

1
2 3 4 5
9