# Questions tagged [atomic-radius]

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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### Comparison between van der Waals radius and metallic radius

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 ...
30 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?
60 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 ...
23 views

### Contraction in Lanthanides and Actinides

How does the lesser shielding effect of 5f electrons(relative to 4f electrons) reduce the change in atomic radius (here, metallic radius) between 2 consecutive elements in Actinides (when compared ...
351 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 ...
159 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 . ...
51 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 ...
53 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 ...
57 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 '...
26 views

### Shielding effect on an electron

Whenever we calculate the screening constant on an $\ce{f block}$ element, we start calculating from the electron present in the $\ce{(n-2)f orbital}$ and then leftwards. I was a bit confused that ...
95 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 ...
63 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, ...
48 views

### Gap in ionic radii

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 ...
74 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 ...
153 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?
914 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 $\ce{Be}$...
83 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 ...
67 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 ...
283 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 ...
4k views

### Which has a greater atomic radius, Cl- , K+ , S-2 , Ca+2 , Ar? [duplicate]

How can I know that? I only know that while we going to the right side at the table so the radius is decreasing. And while we going down, so the radius is bigger. But how can I check that radiuses ...
197 views

### Mismatch in the trends of atomic size and atomic radius

In the periodic table, the atomic radius decreases as we move from left to right in a period. However, the atomic volume should also decrease as a result of the decrease in atomic radius, as volume is ...
366 views

### Radial probability curve [closed]

Can somebody give me a clue on how to solve the question in the picture for me given below
148 views

### Comparing size of ions lithium, gallium ions

How is the size of $\ce{Li+}$ ($\pu{0.68}$) larger than $\ce{Ga^3+}$ ($0.62$)? This is very difficult for me to understand why they say that size of Li+ with 3 protons and just 2 electrons should be ...
176 views

### For a given period, why is the boiling point of the halogen greater than that of the noble gas?

The boiling point of bromine, a halogen, is $\pu{58.8^\circ C}$, while the boiling point of krypton, the noble gas in the same period as bromine, is $\pu{-153.4 ^\circ C}$. I thought that the larger ...
721 views

### What is the difference between the mean radial distance and the most probable radial distance of an orbital?

I was reading JD Lee's Concise Inorganic Chemistry and it has given some values of mean radial distance which is increasing from s to p to d orbital. I had earlier read that the most probable radial ...
1k views

### What is the atomic radius of chlorine?

I'm trying to study for chemistry and there's a question in my book about identifying an element based on its atomic radius. But when I looked up the value for chlorine, I found different answers from ...
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### Is significant figure important for atomic radius calculations? [closed]

Is significant figure important for atomic radius calculations? Calculate the radius of a vanadium atom, given that V has BCC crystal structure, a density of $\pu{5.96 g/cm^3}$, and an atomic ...
3k views

### Why is the difference between atomic radii of Na and K greater than that of Rb and Cs?

I am aware that this question has already been asked here: Why does the "gap" between atomic radii get smaller down the periodic table?. However, I was wondering if there is a way to ...
4k views

### Atomic radius and nuclear effective charge in a group [closed]

Why even though the effective nuclear charge increases in gruop from top to bottom , the atomic radius increases too? Shouldn’t it decrease with more effective charge on valance electrons and ...
3k views

### Niobium has a density of 8.57 g/cm3 and crystallizes with the body-centered cubic unit cell. Calculate the radius of a niobium atom

Here is my question Niobium has a density of $8.57 \pu{g/cm^3}$ and crystallizes with the body-centered cubic unit cell. Calculate the radius of a niobium atom. Here is my solution