For questions about the atomic radius - a measure of the size of an atom, usually the mean or typical distance from the center of the nucleus to the boundary of the surrounding "cloud" of electrons.

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### Proof for equation of radial probability distribution curve

So my textbook says the equation for this is $$P(r) = 4\pi r^2\Psi^2$$ It also gives the volume of the shell formula $$\mathrm{d}V = \frac 43 \pi(r+\mathrm{d}r)^3 - \frac 43 \pi r^3$$ which I ...
17 views

### Where can I find data for ionic radii? [duplicate]

Where can I find data for the ionic radius of various ions? I am looking specifically at yttrium ions, zirconium ions, niobium ions, molybdenum ions, chlorine ions, hafnium ions, tantalum ions, and ...
1 vote
230 views

### Atomic Radius of Manganese and Chromium

It is clearly a general trend that the atomic radii of the 3d elements in ascending order of atomic weight, leads to the following trend as in the graph below. But, it was pointed out to me that, Mn ...
62 views

### Ionic radii of transition metal ions in the presence of weak field and strong field ligands

‎‎‎‎‎‎‎‎‎ In the graph given in this image,‎ I was told by my teacher‎ that whenever we start filling the eg orbitals there is an increase in the radius because these orbitals face the ligand directly ...
1 vote
195 views

### Why are hydrated lithium ions' radii larger than hydrated sodium ions' radii?

Why are hydrated lithium ions' radii larger than hydrated sodium ions' radii i.e. $r_\ce{Li+(aq)}>r_\ce{Na+(aq)}$? If ionic radii increase down the group i.e. $r_\ce{Li+}<r_\ce{Na+}<r_\ce{K+}$... 2k views

### Which atom is the smallest atom?

Is hydrogen or helium the smallest atom? My teacher said that the smallest atom is the helium atom, but I think that the smallest atom is the hydrogen atom. It has a single electron and a single ...
52 views

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### Why does dissolved oxygen concentration decrease with increasing atomic number of metals?

I am looking at how metal ions ($\ce{Fe^2+}$, $\ce{Ni^2+}$, $\ce{Cu^2+}$, $\ce{Zn^2+}$, and $\ce{Ag+}$) affect the biochemical oxygen demand in water and used the Winkler's method to find out the ...
103 views

### Distance of subshells from nucleus [closed]

Which subshell is more closer to the nucleus.4f or 6s? 6s gets filled first so does it have to be more closer to the nucleus?
66 views

### Forcing atoms closer together [closed]

Is there a method in chemistry to alter the energy of atomic bonds by forcing atoms closer together in a smaller volume? Similar to how pressure squeezes atoms closer together.
611 views

### Covalent atomic radii: oxygen vs nitrogen

Many books state that $R_\ce{N} > R_\ce{O}$ which is in accordance with the general trend. However, some books say that $R_\ce{O} > R_\ce{N}$ because of repulsion caused by pairing of electrons. ...
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?
121 views

### How to calculate electric force on valence electron?

In order to understand the periodic trends more fully, I wanted to calculate the net force exerted on the electron (with the highest principal quantum number and azimuthal quantum number) of an atom. ...
580 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, ...
129 views

### In the gold foil experiment why didn't thallium form? [closed]

When alpha particles hit the gold nucleus shouldn't they form thallium. More over shouldn't it also ionize the gold or any atom it hits how does it remain unchanged unionized?
1 vote
207 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 ...
29 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?
1 vote
615 views

### Why is the strontium ion smaller than the potassium ion? [closed]

The ionic radius of the $\ce{Sr^2+}$ ion is $\mathrm{132\,pm}$, while the ionic radius of the $\ce{K^+}$ ion is $\mathrm{152\,pm}$. Why is this the case? I would have thought that since $\ce{K^+}$ has ...
955 views

### Why is platinum denser than gold?

The atomic masses of gold and platinum are 196.96657 u and 195.084 u respectively, meaning that (on average) an individual gold atom is heavier than an individual platinum atom. At the same time, the ...
98 views

### True muonium energy levels [closed]

In a true muniom(muon-antimuon atom) do the energy levels match with that of the hydrogen's? The core is lighter for about 100 times but the muon is 100 times heavier than the electron so it would ...
438 views

### Shielding effect of d electrons

In transition elements shielding effect is observed . Due to this zinc shows abnormality in atomic size. But at the same time we also say that gallium has same similar size as aluminium due to poor ...
96 views

### Shielding effects and atomic size [closed]

The atomic size on going from aluminum to gallium decreases because of poor shielding effect of the $(n-1)d$ electrons, but on going from copper to zinc, the size increases due to the same shielding ...
4k views

I was reading about different types of atomic radius. It was written that if any atom can possess all the three types of radius, then van der Waals radius will be greater than metallic radius. However ...
134 views

### Size of atomic shells

Is the distance of some $n^{th}$ shell ($n$ $\neq$ outermost shell) from the nucleus of an atom different for different elements? If so, then how much is the difference or how could we calculate it?
1 vote
294 views

### Bohr's postulate of quantisation of angular momentum

The Bohr's postulate of quantisation of angular momentum can be written in a formula as $mvr = nh/(2π)$ where $m$ is mass of electron $v$ is its velocity $r$ is the radius of that shell $h$ is Plank's ...
1k views

### Do K+ and F- ions have the same ionic radii? [closed]

Since fluorine and potassium form ions to gain the electronic configuration of neon and argon respectively, then shouldn’t $\ce{K+}$ have a greater radius, as argon is larger than neon? Also which ...
695 views

### H and H- atomic and ionic radius [closed]

A hydrogen anion has a bigger radius than neutral H . Why is this happening ? I mean both electrons exist at the same shell so this is not it. Both H- and H have 1 proton so this is not it as well . ...
86 views

### Do external electronic shells influence internal ones?

There is a well-known electron shielding effect: negatively-charged internal electronic shell screens external shells from positive nuclei, thus increasing their radii. Thus, 2S orbital radius of Li ...
1 vote
138 views

### What will happen if electron as a wave undergo destructive interference while travelling in its Orbit?

Today I came across a justification of Bohr's angular momentum quantization using the De- Broglie's hypothesis. The justification said that since the electrons are having wave nature also then while ...
103 views

### Why are atomic radii calculations all over the map? [closed]

If you look up an element on Wikipedia, it will list covalent, ionic, Van Der Waals, high-and-low -spin, and finally 'empirical atomic radius'. Then, on the page for atomic radius, the chart of '...
1 vote
352 views

### Relationship between electronegativity and atomic radius [closed]

Would someone please explain in detail the relationship between the two? I understand that atomic radius is related to ionisation energy but I can't see how atomic radius may be related to ...
1 vote
75 views

### Do magnesium and tin have the same volume?

Having the same atomic radii of 145 pm, should one mole of tin and one mole of magnesium take up the same volume? Since tin is much heavier, that means tin is much denser than magnesium. Is this true, ...
69 views

The above picture was shown in a presentation by my prof in inorganic chem as we were discussing ionic radii more in depth (all in pm). These are all isoelectronic radii. Notice the sudden leap in ...
569 views

### Lanthanoid Contraction

Why is the radius of Europium so unusually high and out of the general trend ? Moreover, at different sources I am getting different values of radii. In some (e.g., Wikipedia) the radii are following ...
285 views

### Radius with Bohr model [closed]

$$r_n = \left(\frac{h^2}{4\pi^2me^2}\right)\times\frac{n^2}{Z}$$ Would I be able to calculate the radius of sodium ion ($\ce{Na+}$) with the help of the above Bohr atomic model formula?
1k views

### Why does the beryllium 2+ ion have a larger radius than a helium atom?

$\ce{Be^2+}$ has an ionic radius of $\pu{45 pm}$, while $\ce{He}$ has a radius of only $\pu{31 pm}$. If they are isoelectronic (they both have two elections in the $\mathrm{1p}$ orbital), and $\ce{Be}$...
355 views

### Why are the Covalent Radii of Ruthenium and Osmium So Similar?

Osmium and Ruthenium have covalent radii 144 and 146 respectively (according to Wikipedia). How are these values so similar when Osmium has 32 more electrons, with another filled p, s, and f orbital ...
76 views

### How am I supposed to answer this? [closed]

First the question gives no units or that these are covalent radii or what, so I assume they are in nanometers and assume an atomic radius. I check my periodic table app and it says a 92pm atomic ...
626 views

### How to get ionic radii for coordination number 12?

I am studying $\ce{ABX3}$ perovskites, and I would like to calculate Goldschmidt tolerance factors for them. The $\ce{A}$ sites in these materials have a coordination number $12$. The Shannon's ...