A basic unit of matter that consists of a dense central nucleus surrounded by a cloud of negatively charged electrons.

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Are the rules proposed by slater for the calculation of Z effective right?

Today, I studied Slater's rules for calculating the effective nuclear charge. But, one particular line " The shielding power of the d and f orbital is lesser in comparison to the p and s orbitals" ...
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361 views

What holds atoms together?

1.I know atoms are held together by Ionic and Covalent bonds and i understand the ionically bonded atoms are held together by electrostatic forces. What about covalent bonds? 2.How are molecules of ...
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34 views

What is the structure of the Nucleus? [closed]

The structure of an atom is well known to me as something like this: But what is the accurate structure of the Nucleus ? What is the arrangement of the Protons and the Neutrons or any of the other ...
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Conversion of one atom to another to get the element of the latter atom in abundance

One child who is in 9th standard has claimed to have find a solution to all practical physical problems. On asking for details, he said that all periodic elements has common components, i.e. ...
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32 views

Can the electron configuration of Te be written that way?

Normally, the electron configuration of Te is known as: $$\begin{aligned} {[Kr]} 5s^2 \ce{4d^10} 5p^4 \end{aligned}$$ Then, one day I was asked in a exam if this can be written also as: ...
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75 views

An atom of silicon in its ground state has how many electrons with quantum number l = 1?

I was solving practice problems for electron configuration and periodic table, and I got stuck through a question: An atom of silicon in its ground state has how many electrons with quantum number l ...
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643 views

Why do atoms “want” to have a full outer shell?

Okay, so I know that this is about filling the orbitals of the atom, and I understand that. What I don't understand is why? For example, an Oxygen atom has 8 protons and 8 electrons spinning around ...
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41 views

Converting from Grams to Molecules

I was doing some problems from the textbook on converting between units using dimensional analysis and I came across this problem. A vat of Hydrogen Peroxide ($\ce{H2O2}$) contains 455 grams of ...
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56 views

Hydrogen bond question

Can anyone help me with this question I have tried everything. I know hydrogen bonding is with F,O, or N but every time I select those is says it's wrong. Any help is appreciated
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Why there are different elements in nature? [closed]

Why there are different elements in nature with different chemical properties while all atoms are made from three subatomic particles? Are these different elements have been created accidentally, or ...
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Is a single 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 ...
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117 views

What actually is the Wavefunction?

I am aware that the square of the Wavefunction gives the probability density of finding an electron at a particular point in space. I have also heard that it's a complex number but since it's a ...
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41 views

atomic mass chemistry chang

there are two stable isotopes of iridium Ir (190.96) and Ir (192.96) if you randomly pick an iridium atom from a large collection of iridium atoms which isotope are you more likely to select ??
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57 views

Whats the difference between ionization energy and orbital energy?

If you look at the trend in orbital energies as you go across a period the pattern is clear (orbital energy decreases with increasing effective nuclear charge) and, to my knowledge, it has no ...
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44 views

Potassium Atom can act as reducing agent, yet ion cannot?

I am currently looking through a revision sheet, however it has caught me on a question 'Explain why a potassium atom can act as a reducing agent yet a potassium ion cannot'. I have done brief ...
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90 views

How can two orbitals constructively and destructively interfere simultaneously?

The molecular orbital theory dictates that when two atomic orbitals form molecular orbitals, then two molecular orbitals must form (i.e number of atomic orbitals = number of molecular orbitals). For ...
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62 views

Which is the bigger ion, F- or O-?

Well, according to the proton-electron ratio $\ce{O-}$ should be bigger than $\ce{F-}$ What about the charge/electron density in $\ce{F}$? Will it not affect the size of the atom of $\ce{F-}$?
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51 views

Can you calculate the properties of a substance based soley on its atomic properties?

I'm trying to write some software that I can use to determine, roughly, what the physical properties of a pure substance are. I know I could just use a database of the known properties of each ...
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140 views

How can we measure atomic radius of atom?

The definition of atomic radius is ha;f the average internuclear distance of a atom. But many times it have been told to me that it is not possible to handle single atom, then how can we measure the ...
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31 views

How does the vacuum in atoms persist?

From very elementary chemistry I understand that atoms are mostly empty space, with a few tiny little objects whizzing around. There must then be a vacuum in between these particles. I always thought ...
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Explaining Ionization to kids

I have a quest to explain a physical, chemical theory to kids of age 8-12. The topic is "Ionization". We all understand from early experiments of Physics and Chemistry (the Millikan oil drop ...
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96 views

Why can't light pass through a gold foil, but alpha particles can?

Rutherfords experiment showed that most of the alpha particles passed through a thin gold foil undeflected. So why can't light pass through the foil, which is supposedly thinner than the heavy alpha ...
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95 views

How can two electrons lie together in an orbital?

Two electron of opposite spin can lie in a single orbital.. But what about the electron-electron repulsion. Okay! I got that the nuclear charge rather the large Z-effective overcome this repulsion by ...
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279 views

Difference between actual position of electron and Radial Distribution Probability

Its known that the radius of maximum probability of 2s orbitals is more than that of 2p orbitals. It means that the maximum probability of finding an electron in an 2s is further away from electron ...
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Why did Dalton assume that atoms are spherical?

One of the primary components of Dalton's theory is to "express" an atom as an unbreakable spherical shape filled with whatever. The question is, why didn't he suggest any other shape, like for ...
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Find n and the wavelength too

To start with its a homework problem, quite lengthy. A particle of mass equal to 208 times the mass of electron moves in a circular orbit around a nucleus of charge +3e. Assuming the BOHRs model of ...
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39 views

Protons or electrons are responsible for chemistry of an atom?

Is the question in a correct form? I can't add anything as a comment. Thank you.
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Atomic radii of Sc,Ti and Fe,Co

The atomic radii of Sc is 162pm , Ti is 147pm , Fe is 126pm and that of Co is 125pm. Electronic configuration of Fe is (Ar)3d6 4s2 and that of Co is (Ar) 3d7 4s2. Difference of Z between them is 1 ...
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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 ...
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56 views

What happens when we heat an atom?

Question is simple.. If we take an atom of any element and then supply heat energy to it then what will happen? Acc to me in beginning energy[quanta(due to excitement of electron and then moving ...
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46 views

Bombarding atoms with electron gun?

Just to explain this question in a better way just think about the Rutherford's experiment(the alpha particle bombarded on Gold foil) be conducted using a electron gun in place of the Alpha one.. So ...
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105 views

The definition of formal Charge

Ok, most people including me know that formal charge is just a book-keeping tool. I know how to calculate it, apply it to Lewis structures etc etc. But I am confused in its very basic definition which ...
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58 views

Greater entropy: an atom or macromolecule?

A question that appeared on my last chemistry exam was : Which of the following has greater entropy A) An atom B) A macromolecule The question doesn't specify anything else(i.e. type/size ...
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51 views

Wavelength of X-rays

What will be the wavelength of X-ray if we apply a potential difference of , say 20 KV across the ends of the x-ray tube ? Alright, i started with the modified de-broglie equation ...
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68 views

Intermolecular Hydrogen Bonding

I learnt about intermolecular hydrogen bonding today, which occurs between molecules such as ortho-nitro-phenol. What I was told is that in case of intermolecular bonding, the molecules separate from ...
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113 views

Why are atom spherical in shape ?

I am learning about structure of atom, in which i saw right from J.J. Thomsom atomic model to modern nuclear atomic model all are spherical in shape. I have seen how different discoveries help to ...
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80 views

Shells, orbitals, subshells, and energy levels

I think i Know what these mean, each row on the periodic table has a new shell of electrons, a subshell is e.g. 1s, 2s, 2p, 3s, 3p, etc and energy levels are the same as shells whilst orbitals are the ...
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79 views

Why don't alkaline earth metals lose only one electron when they are ionized?

Why doesn't alkaline earth metals lose only one electron when they are ionized ? I know that magnesium atoms like to have the electronic configuration of neon but I don't understand the reason that we ...
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63 views

Find the uncertainty in position

The question says: A proton is accelerated to one tenth of the velocity of light. If it's velocity can be measured with a precision $\pm 1\%$. What must be its uncertainty in position? Therefore, ...
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96 views

Calculating Avogadro's Number

For a school project, I am in a group tasked with calculating Avogadro's Number in multiple manners. Other than the Millikan Oil Drop Experiment, we know of no ways to compute it. A Google search ...
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110 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). $$ \frac{\frac{4}{3}\pi(7*10^8)^3*1.4}{1.008} * 6.022*10^{23} $$ ...
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134 views

Law of reciprocal proportion

Is it necessary that the valency of an element must have the same valency? For eg. If 2 elements A and B combine with the same mass of C, is it necessary that they will have the same valency as they ...
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Degenerate Orbitals

How do I know if an atom has degenerate orbitals? My Understanding I understand that degenerate orbitals mean orbitals that have the same energy level for the same n. However, how do I distinguish ...
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211 views

How to calculate m/e value for the base peak in mass spectroscopy?

My working out: Propan-1-ol : CH3CH2CH2OH This can be broken up into: CH3 + CH2CH2OH CH3CH2 + CH2OH CH3CH2CH2 + OH Base peak = most abundant fragment formed (highest peak) How do i know which ...
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138 views

Is it possible to compress an atom to infinite density?

I know, by nature, normally atoms are stable. But I wonder, if it is possible to compress an atom, say the Hydrogen atom, to infinite density by applying external force? After all, electrons and ...
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Are atoms really round?

I'm not sure if this is a silly question, but I was sitting here with a cup full of cheezey poof balls thinking, "My goodness, it's like an amazing cheesey delicious liquid - huge water molecules!" ...
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Why does free chlorine in the stratosphere lose its ozone-depleting potential after about 100,000 reactions?

Free chlorine ($\ce{Cl}$) in the stratosphere can deplete ozone ($\ce{O3}$) as follows: $$\ce{Cl + O3 -> ClO + O2}$$ The chlorine atoms can then react with oxygen and return to the beginning of ...
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123 views

Number of molecules and atoms are same in a gas, how?

I had a test this morning in school and I am not sure of the answer,I think it is related to the quantity of a mole being constant: A sample of certain mass of gas was collected and it was found that ...
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28 views

Comb and hair, is that an example for ionic boding?

As i understand, when brushing hair, some electron transfer from hair to the comb. Thus, make the comb have different charged from hair and they attract each other. It's look likely what i have learn ...
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67 views

Ground state electron configuration of chromium

What is the ground state electron configuration of chromium? Is it [Ar]4s23d4 or Is it [Ar]4s13d5