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.

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1answer
22 views

Alternative to a proton [on hold]

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) ...
0
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0answers
19 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
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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
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1answer
31 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
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1answer
25 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
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0answers
34 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
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1answer
70 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
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1answer
27 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
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1answer
22 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
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1answer
84 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
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1answer
285 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
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1answer
274 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
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2answers
692 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
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1answer
57 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
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1answer
68 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
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1answer
83 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
1k 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?
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1answer
63 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
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2answers
37 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 ...
12
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2answers
852 views

Protons and the Heisenberg principle

The Heisenberg uncertainty principle implies that it is not possible to calculate the position and velocity of a body at the same time accurately. Electrons follow this principle since their orbitals ...
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1answer
68 views

Can anyone give me detailed logical solution to my questions? [closed]

What is 1 amu? From where it is derived? Why it is compared with carbon-12? Why it was once compared with hydrogen-1? and now its not? Can anyone please explain me logically? And what would have ...
0
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0answers
18 views

How octet configuration of atoms make them stable? [duplicate]

How the octet configuration of atoms making the atoms stable? How it helps them?
2
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0answers
59 views

Why are the d-orbitals so named?

Why are the $d$-orbitals so named? The naming of $p$-orbitals is fine. I can easily name any p orbital according to the axis along which it is oriented. But what about $d$- orbitals? Why are there ...
0
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0answers
52 views

Mass number, (relative) atomic mass, average mass

What is the difference between mass number, atomic mass and average atomic mass? I know the mass number is the amount of protons + the amount of neutrons. The average mass is the weighed average of ...
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1answer
67 views
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1answer
119 views

Why is there no neutron in protium?

My chemistry teacher told me once that every atom should have at least as many neutrons as protons, to keep the electrons from crashing into the nucleus. Protium, however, does not have any neutrons ...
1
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1answer
152 views

How many atoms of helium are in the chamber?

A $22.7 \,\mathrm{L}$ helium-filled chamber at $298\,\mathrm{K}$ has a tiny hole of area $1.63 \times 10^{-5}\,\mathrm{mm^2}$ punched in it through which is leaking helium at a rate of $2.25 \times ...
0
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1answer
28 views

Do you refer to a bonded atom as an “ion”?

Take H2O, would you call the H a hydrogen ion? Or just a hydrogen atom?
2
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1answer
340 views

Is there a relationship between an electron's energy and its distance from the nucleus?

I have read that in Bohr's model of the atom electrons in the same atomic orbital have the same energy, and that this energy (as a result of the electron existing in a fixed atomic orbital) is related ...
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1answer
104 views

Number of H atoms in 0.5 mol [closed]

How would I calculate the number of hydrogen atoms in 0.5 mol? I presume the answer would probably somehow use the {moles = mass/molar mass} equation but I'm not sure how to calculate it.
5
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2answers
93 views

Why do electrons need to be paired?

I’d read that it takes energy to place electrons in pairs, just less than it would take to place two electrons in different subshells. I get that. What I don’t get is, then, why would electrons want ...
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0answers
21 views

Can Barium 141 react with 6 protium molecules? If so, can this lower the overall half life of nuclear waste? (Barium 141, Krypton 92)

I have a theory, but I have only been in highschool Chemistry for a week so it might not be a good one. Our teacher is making us debate wether nuclear fission is an efficient way to create energy. I ...
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1answer
469 views

How do I find the diameter of an Aluminum atom? [closed]

I am supposed to find the diameter of an Aluminum atom using data given by my teacher. Here is the data: ...
-1
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1answer
57 views

Molecules aren't the same as atoms?

Question is simple but tricky, for example my chemistry teacher says that preservatives on food for example Nitrate N3 are not good in excess for your body (like everything else), but if Nitrogen is ...
1
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0answers
32 views

Does the value of magnetic quantum number specify a certain orbital? [duplicate]

I understand that magnetic quantum numbers represents orientations of orbitals. I want to know if a specific value of 'm' pertain to a certain orbital? Ex- For p-subshell, the values of 'm' can be ...
12
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5answers
1k views

Elements and atoms

First, I would like to quote sentences from a book introducing elements and atoms: An element is a fundamental (pure) form of matter that cannot be broken down to a simpler form. Elements are ...
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0answers
41 views

Experimental Validation of Schrodinger's Electron Cloud theory

I am currently doing a report for school on the electron cloud atomic structure theory. One of the major points on my report is the experiments performed by the scientists (Schrodinger and Heisenberg) ...
2
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1answer
558 views

How do scientists count the exact number of electrons, protons, neutrons in the atom?

An atom is very small so it is probably difficult to focus exactly on a single atom. I wonder how scientists count the exact number of electrons, protons, neutrons in an atom of a certain element. ...
1
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0answers
70 views

Why don't electrons just crash into the nuclueus? [closed]

This question has already an answer on Physics.SE: Why don't electrons crash into the nuclei they “orbit”? I've seen some answers to this questions on google, but they don't go into really ...
5
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1answer
208 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?
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0answers
28 views

How would I find an apporpriate dopant element for a lattice

I am trying to figure how would I go about finding a dopant element that would fit in a copper lattice? I already have the data for the atomic dimensions and structure (available below), however how ...
1
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2answers
360 views

Periodic Trends of Zeff and Electronegativity

The effective nuclear charge $Z_\mathrm{eff}$ increases from left to right and from top to bottom. Can you explain why it increases from top to bottom? Also can we explain the periodic trend of ...
2
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1answer
40 views

Electron's Energy In The Atom

I know that the exact (OK most of the times not the exact) energy of an electron can be calculated by solving Schrodinger's differential equation, but can we explain an electron's energy of a specific ...
2
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1answer
58 views

Confused about writing out electron configurations

I watched the Crash Course chemistry video about the electron. In the video Hank showed an example configuration of iron as $\mathrm{(1s)^2 (2s)^2 (2p)^6 (3s)^2 (3p)^6 (4s)^2 (3d)^6}$ and explained ...
2
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0answers
130 views

Few basic questions about ionic bonding and batteries (lead)

I've got a few very very basic questions about ionic bonds and their role in batteries. My assumptions (correct me if I'm wrong): Ionic bonds occur between a metal and a non-metal (the non-metal ...
1
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2answers
400 views

Does Bohr's theory violate the Uncertainty Principle?

In a book, it is stated that one reason for the failure of Bohr's theory was the fact that it violates the Uncertainty Principle. Is this fact true? if so, explain to me how it violates the ...
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0answers
23 views

What determines the color of a object? [duplicate]

Why is gold yellow for example? Which property of the atom determines the color?
16
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3answers
2k views

How do I visualize an atom?

I have searched and searched, oh how I have searched. I am looking for a 3-dimensional visualization of a whole (i.e., moderately complex) atom that includes orbital geometry. A proper "layered" view ...
2
votes
1answer
82 views

The proper explanation for the general formula of the DU? [duplicate]

I found a formula for the degree of unsaturation (DU) in Clayden’s Organic Chemistry. It explains, simply, the unsaturation with the difference in H atoms. Then I stumbled upon the general formula: ...
0
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0answers
20 views

Do we have a reasonable assurance that relative atomic mass is constant throughout the universe? [duplicate]

I know atomic mass can be (over) simplified as the average mass of all isotopes of a given element weighted by the ratio of their natural occurrence. I also know that, as far as we know, refining ...