Smallest particle still characterizing a chemical element. It consists of a nucleus of a positive charge, carrying almost all its mass and electrons determining its size. This tag should be applied to questions that specifically concern these particles and their properties.

learn more… | top users | synonyms

0
votes
0answers
26 views

Why does greater orbital overlap mean a stronger bond?

According to valence bond theory, orbital overlap produces a bond. However, I don’t understand why having greater orbital overlap renders a bond stronger. It’s intuitive, I suppose, but I haven’t been ...
0
votes
0answers
23 views

Atomic Structure History [on hold]

I would like to ask about the history of atomic structure discovery. -- Rutherford proposed the "miniature solar system model", and he suggested Hydrogen, which has the smallest atoms, would have ...
4
votes
1answer
84 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])....
-1
votes
0answers
18 views

Energy gap between 4d and 5f orbitals

As we know 4d orbital initially has lower energy than 5f orbital but upon filling 1 electron into 4d orbital its energy generally rises and exceeds the energy of 5f orbital. Why does not after filling ...
-3
votes
0answers
24 views

revolution of electrons around the p orbital

We know that electrons revolve around nucleus in circular orbits. If we see the shapes of different orbitals, we find that s orbital is spherical so electrons can easily revolve around it, but in case ...
-1
votes
0answers
32 views

Why does having a lone pair makes an atom more electronegative?

I was reading the dipole moment and came across the structures of NH3 and NF3. I understood that the net dipole moment of NF3 is lesser, but could not understand the fact that why would a lone pair ...
1
vote
3answers
63 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 ...
0
votes
1answer
24 views

Avagadro's number [duplicate]

Ive been reading about moles and I can't seem to understand avagadro's number. I get that the idea is 1g of hydrogen, 12g of carbon, and 16g of oxygen would all have the same number of atoms, but why? ...
3
votes
1answer
46 views

Why is Dulong and Petit's law not applicable to Be, B, C, Si?

Dulong and Petit's law is useful for calculating the approximate atomic mass of an element when its specific heat is given. My book says that Dulong and Petit's law is only applicable to solid ...
4
votes
1answer
41 views

Different masses for the same element and isotope?

I am watching this Khan Academy video on mass defect and binding energy, it uses helium-4 as an example to go through the concept. The person finds the predicted mass (protons + neutrons) to be 4....
1
vote
0answers
33 views

Understanding three-dimensional structure of common salt

I started reading through The Feynman Lectures and came across this diagram. What do the numbers next to the nodes in the diagram represent? It's not explained in the text. All that is mentioned is: "...
2
votes
0answers
59 views

Doubt about Rutherford's experiment

In Rutherford's experiment to show the existence of nucleus in an atom, the alpha-particles were exposed on the surface of certain metal i.e. gold. He observed that more than 99% of these particles ...
0
votes
1answer
43 views

Spin of electrons about it's own axis, release of energy & COLLAPSE of atom? [closed]

An electron spins about it's own axis. So it has rotational accln. Thus, according to Maxwell's Electromagnetic Theory , Rotational Kinetic energy must be released. Thus, at some pt. of time , ...
0
votes
2answers
76 views

What is the reason why protons and electrons do not collide?

can someone give me an intuitive picture of why electrons don't collide with protons? I know that electrons move in a sort of cloud, which is our 'orbital', and that they mainly behave like ...
1
vote
0answers
36 views

Why are Alkali Metal Ions Soluble?

I think the question needs no elaboration. Why are salts containing Group 1A cations extremely soluble in water? I speculate that the reason involves the low charge density of those ions in a given ...
0
votes
0answers
24 views

Size of Germanium compared to Silicon

Gallium has a smaller atomic radius than Aluminum because of the poor shielding effect in Gallium due to the presence of 3d orbital. However why does this not happen with Germanium and Silicon, ...
0
votes
0answers
24 views

table of expanded electronic structures of atoms

Where can I find the table containing expanded electronic configurations for atoms in periodic table, showing how outer electrons are distributed between different atomic orbitals? Well, i need just ...
0
votes
1answer
19 views

What is generally meant by distinct line spectrum?

In a single hydrogen atom the electron is excited to 6th orbit. The book says maximum 5 distinct spectral lines are possible when the electron comes to the ground state. Looks like they have only ...
-1
votes
1answer
41 views

Why most of the atoms with fully filled outer orbits are gaseous?

Most of the elements with fully filled outer orbits are gaseous in nature (He, Ne, Ar, Kr, Xe, Rn) with exception of Uuo (as per Wikipedia its solid). Why these fully filled outer orbit elements are ...
0
votes
1answer
42 views

A problem on rate of diffusion

At a particular temperature and pressure it takes just 8.256 minutes for a 4.893 liter sample of Neon (Ne) to diffuse through a porous membrane. How long will iodine diffuse in similar conditions? ...
2
votes
0answers
64 views

Is a substance's band gap related to it's flame test colour?

This is really not my field at all, but I am intruiged by the cause of different metals emitting different wavelengths of light. To my knowledge, the more energy needed to "excite" an electron, the ...
1
vote
0answers
41 views

Difference in properties between a substitutional and an interstitial alloy?

What I know is, that in a substitutional alloy, the atoms of the solute metal take positions normally occupied by the solvent metal atoms, as they are more or less the same size. In an interstitial ...
6
votes
2answers
272 views

The effects of adding neutrons to an atom

So neutrons are neutral in terms of charge, and adding neutrons to an atom affects its atomic mass. But when neutrons are added to the nucleus, the nuclear radius would be affected. Couldn't that ...
0
votes
1answer
90 views

What are the height and width of the large and small nodes of the sp3 hybridized orbitals of carbon and silicon?

I will make an effort to interpret answers based on wave functions, but I am a senior pursuing a bachelor's degree in Biology, so I don't have the background in quantum physics for a purely ...
1
vote
1answer
36 views

Find the amount of atoms for a given mass

The atomic mass of two elements A and B is 40 and 80 respectively. If x g of A contains y atoms, how many atoms are present in 2x g of B? I have tried to solve by assuming that x g of A has y atoms ...
0
votes
1answer
42 views

Numerical value of mole

Why is the numerical value of a mole of atoms equal to the atomic weight? For example, hydrogen has an atomic weight of 1.008, so 1 mole of hydrogen atoms has a molar mass of 1.008 g/mol. Why?
5
votes
2answers
716 views

Can we recycle garbage with the principles of mass spectrometry?

'Mass Spectrometry (MS) is an analytical technique that sorts ions based on their mass (or "weight"). Mass spectrometry is used for many chemical analyses, ranging from the analysis of a complex ...
0
votes
2answers
98 views

Is nucleus at the centre of the atom? If so why?

In postulates of Bohr's model of the atom, it is said that the nucleus is at the centre of the atom. In Rutherford’s α scattering experiment he said that out of 20,000 alpha particles only 1 ...
0
votes
1answer
64 views

How can I search molecules by constituent atoms

Given a set of atoms, I would like to find (some / the most common) molecules that include only (some/all) atoms of the set. Is there any online search engine that can do this? E.g. Atoms={C,H} ...
1
vote
1answer
82 views

How to calculate Madelung's constant for NaCl?

Madelung's constant for $\ce{NaCl}$ is $1.748$. What I tried to so is sum up all the individual interactions into $1$ component where the $X$s are the nucleus and the electron if it was a $2$ atom ...
0
votes
0answers
88 views

Why does the electronic distribution of Calcium is 2,8,8,2 when 3rd shell(M shell) can hold 18 electrons?

I know by the formula 2n^2, the total no. of electrons in K, L, M, N shells are 2, 8, 18, 32 respectively. But here electronic configuration of Calcium is not correct if we go solely by this formula. ...
-2
votes
1answer
34 views

Alternative to a proton [closed]

I know I might sound terribly stupid but the idea just hit me. We define elements on the periodic table as "lumps" of matter with specific amount of specific particles (electrons neutrons and protons) ...
1
vote
0answers
88 views

Anomalous Electronic Configuration of Thorium

The electronic configuration of thorium ($Z=90$) is $5\mathrm f^0 6\mathrm d^2 7\mathrm s^2$. But, according to the aufbau principle, the electrons should first enter the $\mathrm f$ subshell and not ...
0
votes
0answers
20 views

How do I calculate the valence(y) of an element, knowing it's valence electrons [duplicate]

How do I calculate the valence(y) of an transition metal or just any element in the periodic table? I know it has something to do with valence electrons(The electrons in the outer most shell, right?), ...
0
votes
1answer
46 views

How to find electronic configuration of an atom? [closed]

I would like to know how to find the electronic configuration of an atom such as Potassium without using the 1s2, 2s2, 2p6 ... method to explain as I don't get it at all. Try to orientate the answer ...
1
vote
1answer
34 views

Why does ionization increase from Li to Be? [duplicate]

If ionization energy decreases from $\ce{N}$ to $\ce{O}$ due to the pairing of electrons (causing electric repulsion and greater potential energy) in the $\mathrm{2p}$ orbital in the $\ce{O}$ atom, ...
1
vote
0answers
52 views

Use of statistics in this field

I am currently pursuing a statistics course and I an interested in knowing how can statistics help this field in future. (I am interested because I love chemistry very much) Specifically, are there ...
0
votes
1answer
120 views

Which statement is correct about electron orbitals and energy levels?

Which statement is correct about electron orbitals and energy levels? A. Yttrium, $\ce{Y}$ ($Z = 39$) is the first element in the periodic table with an electron in a f sub-level. B. The ...
2
votes
1answer
63 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 ...
0
votes
1answer
89 views

Ionization energy comparison between K+ and Cl-

So I have encountered a question which looks very suspicious to me. If you have $\ce{Cl-}$ and $\ce{K+}$, Can you say that $\ce{K+}$ has more ionization energy than $\ce{Cl-}$? We know for a fact ...
3
votes
1answer
118 views

Why is it easier to determine the radius of inert/noble gases?

My textbook says it is possible to determine the atomic radius of the inert gases like He, Ne, Ar etc because they roam freely and are incapable of forming bonds. However it is very difficult to find ...
5
votes
1answer
308 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 ...
8
votes
1answer
284 views

Existence of orbitals

Do orbitals exist even when they are not occupied? For example: $\ce{Cr^{+3}}$ has the configuration $\ce{[Ar]}\mathrm{3d^3}$ with the other two $\mathrm{3d}$ orbitals empty. We know the other two ...
2
votes
2answers
2k views

Is iron the most stable element in the periodic table?

According to the binding energy per nucleon vs mass number graph, it is observed that iron-56 has the maximum value of binding energy per nucleon (8.75 MeV).It means that Iron-56 is the most ...
0
votes
1answer
86 views

Can we add an electron to an atom?

Say that we have an atom which is inert, or stable. How would one go about adding one electron. Is it possible?
0
votes
1answer
276 views

If the reactivity of group 1 elements increases down the group, why is this not the case for halogens?

I was wondering, as you go down a group, the atoms get bigger... This means that the electrons in the outer shell are further away from the nucleus, and so the attraction decreases and it is easier ...
5
votes
1answer
99 views

What is the electron configuration for Uuo with a charge of 2-?

I was writing a cool program that determines the electron configuration of elements for me, and I wondered what would happen if you went over 118 — the "limit" of my program. So, what is the ...
3
votes
1answer
3k views

How many valence electrons does an atom of Cu have? [duplicate]

$\ce{Cu}$ electron configuration: $\mathrm{4s^1 3d^{10}}$. Ok so the answer is $11$, shouldn't it be $1$ since the $\mathrm{d}$ shell is already filled up?
-2
votes
1answer
78 views

How is Molecular mass is the molecular weight? [closed]

Wikipedia says molecular weight is the mass!! I can't get it the weight is the mass times 10 so we cannot neglect that, because 10 amu is not equal to 1 amu
1
vote
2answers
67 views

Is water a heterogeneous molecule? [closed]

My question is based upon the statement found here: an element may be homogeneous on a larger scale, compared to being heterogeneous on a smaller scale. This is known as an effective medium ...