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Questions tagged [periodic-table]

This tag should be applied to questions about the layout, history and interpretation of the periodic table, not to questions relating to specific elements or trends within the table. For these, the tags 'elements' or 'periodic-trends' should be used where appropriate.

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12
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3answers
397 views

What is the usage of orbitals more complex than f orbitals?

Every high school learner, in each corner of the world, faces the lesson History of Atom during his courses, just as I did. We learned about s, p, d and f orbitals, though there were no signs of ...
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1answer
3k views

Periodic trends: why is effect of protons greater than electrons?

Why is it that adding protons has a greater effect than electron-electron repulsion on periodic trends like atomic radius and ionization energy (assuming # of shells constant)? It seems that if ...
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1answer
584 views

Show which group the element with Z=31 belongs

and I understand it belongs to the 13 th group, but my teacher wants to express it as IIIA, so how should I convert it in my mind?
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1answer
365 views

How can we confirm the number of protons in an atom?

The periodic table tells us that there are 6 protons in a carbon atom. Is there a way to verify this first-hand? Or are we just expected to believe it unquestioned?
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1answer
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Outermost electronic configuration of f block elements

Why is it $(n-2)\mathrm{f}^{1-14}(n-1)\mathrm{d}^{0-1}n\mathrm{s}^2$. The only exception I thought to this formula was Thorium $\ce{5f^{0} 6d^{2} 7s^{2}}$. So I feel it should be $(n-2)\mathrm{...
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2answers
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According to what criteria was the periodic table of elements ordered?

I was wondering why the elements in the periodic table were disposed the way they are. I understand, of course, that they are put in increasing atomic number fashion, but I'd like to know more about ...
4
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1answer
583 views

How was Mendeleev able to develop his table?

I asked my general chem instructor this and he didn't know: Mendeleev was able to group elements and discovered a bunch of them and put them in the correct order in the mid-1800s. What equipment did ...
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3answers
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Biological Consequences of Asteroid Mining—Death by Isotope?

It's been documented that NASA hope to capture an asteroid in 2025, and have subsequent aims to mine that asteroid. If if this is successful, we would expect other asteroids to be mined in the future. ...
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2answers
2k views

Does there exist any relation between metallic property and oxidation potential?

I was having a revision on periodic table I was thinking about different properties I could connect most of I could not connect metallic property and oxidation potential .
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1answer
6k views

Order of second iozination energies of lithium,berillium,neon,carbon and boron?

The correct arrange of them is like this: Be < B < Li ... But why? Li will have the greatest IE2 (second ionization energy) because that will involve removing a core electron, but what I am ...
2
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1answer
2k views

Block on the Periodic Table?

What are the blocks of the periodic table? What is the purpose of naming the elements per block group? What do they signify?
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3answers
375 views

Do isotones share any similarities?

A trivial research in atoms and their basic theories led me to this term: "isotones" Nuclides sharing the same number of neutrons but different atomic numbers. A simple request or shall I say, quest: ...
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7answers
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Why lanthanides and actinides are shown separate from standard Periodic Table layout?

In the standard Periodic Table layout , all the elements up to 56 are in order i.e are in the same layout table. However, lanthanides and actinides are always shown separately from the layout like in ...
2
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1answer
4k views

lanthanide contraction

"The Lanthanide Contraction refers to the fact that the 5s and 5p orbitals penetrate the 4f sub-shell so the 4f orbital is not shielded from the increasing nuclear change." First, 5s and 5p are ...
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2answers
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What is the formula for finding the average atomic mass of an element based on the abundance of its isotopes?

In my class my teacher showed us how to find the average atomic mass of an element with a method, but he didn't really state a formula one could use. I came up with a formula of my own, and from what ...
2
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0answers
95 views

Why does sulfur exist as octasulfur? [duplicate]

Sulfur belongs to the same group as oxygen. Then why oxygen exists as an $\ce{O2}$ molecule while sulfur exists as $\ce{S8}$ molecule? What's the chemistry behind this?
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1answer
717 views

What is the most rare element in periodic table

What is the most rare element in periodic table? I have a lot of confusion about this.
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3answers
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Why is lanthanum a lanthanide and actinium an actinide?

I do know that the lanthanides start with the element lanthanum, but why? Lanthanum doesn't even have an $f$ orbital, so why isn't it considered a transition metal? It's the same way with actinium, ...
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1answer
2k views

Memorize Transition Metal Electronic Ground State

In the course of my undergraduate studies it has become clearer and clearer that it is quite helpful to know the ground electronic state of transition metals by heart, if only to speed up the process ...
5
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1answer
675 views

What is the joke that is shown in this picture?

There is supposedly a joke shown in this picture relating to periodic trends. Does anyone know what it is? And could they also explain where the elements on the eye exam came from?
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1answer
4k views

What is the group number or name for elements between group 3 and 4 (F-block) on the periodic table?

What is the group number or name for elements between group 3 and 4 (F-block) on the periodic table? I noticed when I look at a periodic table of elements, the elements of the F-block between group 3 ...
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1answer
2k views

Pair of analogous periods on the periodic table

On the periodic table, period 2 and 3, 4 and 5, 6 and 7 and so on have similar blocks, identical length and groups. What are such pairs of analogous periods called?
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1answer
7k views

Why does Ruthenium only have one electron in its 5s orbital in the neutral oxidation state?

So recently I have undertaken some research with some organometallic chemistry involved, specifically regarding that of ruthenium-aryl compounds. Trying to understand the chemistry of the central ...
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1answer
6k views

How many p-orbitals are there in each period?

How many p-orbitals are there in each period?a. 1b. 3c. 5d. 7e. 14 I take this to mean "how many p-orbitals are there in each period of the periodic table?" Looking at the p-block on the periodic ...
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1answer
251 views

Chelation and its relation to transition metal ligands

Can someone explain chelation and its relation to monodentate and tridentate ligands? I dont understand what they mean by chelate effect and chelating rings.
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1answer
5k views

Oxidation state of group 2 elements

I have came across the following statement : "the oxidation state $+II$ is stable for the elements of the alkalin earth metals" , the same is true for the elements of the first group , i've looked for ...
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1answer
988 views

What is advantage of creating elements that disappear in a flash?

More than dozen of heavy elements of periodic table do not occur naturally but are prepared artificially at nuclear reactors.. These elements are said to disappear in a flash.. So, why invest lot of ...
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3answers
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Diagonal line going through groups IIIA-VIA on the periodic table

Why is there a diagonal line cutting through some of the nonmetals and metalloids on the periodic table in groups IIIA, IVA, VA, VIA, and VIIA? Is there any historical background about it?
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1answer
614 views

How chemists find out the electronic properties of elements (atomic numbers)

How did chemists find how many electrons, neutrons, and protons each element had? I mean I can understand the Mendeleev's table but without really knowing how you make one...
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2answers
122 views

How do the differences in the number of protons result in such great differences in elemental properties?

I understand(I think) the mass and density aspect, i.e. the more protons you have, the more the element weighs, also the denser the atom is. What about everything else(color, for example)? Elements ...
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2answers
985 views

What is the difference between a mixture and a composed substance?

In my textbook it says, that a composed substance is a substance made of more than 1 type of atom. And It also says, in another chapter it says that a mixture is the grouping of more than one ...
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2answers
490 views

Did Mendeleev predict the existence of neutrinos?

According to this Wikipedia page, Mendeleev originally believed that the inert gases belonged in Group 0 (to the left of the alkali metals). Thus, helium would be placed in the second period to the ...
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1answer
53k views

Why are elements on the right side of the periodic table nonmetallic and gas at room temperature?

Elements on the left side of the periodic table tend to be solid and metallic, elements on the right side of the periodic table are nonmetal and tend to be gases at room temperature, and the semi-...
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2answers
3k views

What is a “period” of the periodic table?

I'm familiar with the periodic table / periodic system, but I wonder why it's called "periodic" since there seems not much periodic about (there seems to be little or no predictability of which ...
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2answers
14k views

Where hydrogen belongs in the Periodic Table

Why do some people say that hydrogen should be above lithium in the periodic table and others argue it should be above fluorine?
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5answers
14k views

Why does radium have a higher first ionisation energy than barium?

I'm wondering why radium appears to buck the general trend that first ionisation energies decrease as you move down a group in the periodic table: barium (the group 2 element preceding it) has a first ...
18
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5answers
12k views

Where can I find a downloadable spreadsheet of element properties?

Sorry for the FAQ, but I really don't know where to find a full spreadsheet for element properties. I mean a table that has one row for each element, and the columns are its properties, such as name, ...
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1answer
2k views

What are the g-block's predicted properties?

I have been researching for a Physics/Chemistry exam and thought; what will the future periods in the periodic table (periods 8 and above) would entail? Each block contains its own properties that ...
7
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1answer
1k views

Where did the rest of the elements come from?

There were ninety original elements on the Periodic Table. Over time, new ones were founded and put on. However, they were all either the original elements experimented on. For example, Plutonium was ...
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1answer
7k views

How can scientists be certain that there are no undiscovered elements missing from the periodic table from hydrogen to lawrencium?

Scientists are certain that there are no undiscovered elements missing from the periodic table from hydrogen to lawrencium. How? and why?
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1answer
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Specific heat capacity and the periodic table

Can someone explain me how can I use the periodic table in order to find the specific heat capacities of some elements? (for example, of Aluminium ) The question I have encountered is as follows: ...
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4answers
2k views

Phase diagram for first 10 elements

I've been looking on the net for a reference which shows a phase diagram for elements at least from $\ce{H}$ up to $\ce{Ne}$. Specifically, I'm looking which of these elements can be solid or liquid ...
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1answer
3k views

Determining the exact charge of ions that will be formed by an atom using the periodic table

I don't know how to obtain the "exact charge of the ions" that will be formed by each atom mentioned. I also have to figure out whether they are positive or negative. Hydrogen, for example, can form ...
5
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1answer
1k views

Is there a similar characteristic of the lanthanide contraction in the other transition metal groups?

Basically, does the lanthanide contraction also occur with the 4d, 6d groups as well? I am at a lack of understanding in this topic, I am just wondering what specific elements does this jump in a ...
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2answers
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What are the alternatives to the Periodic Table of the Elements?

What are the different diagrams/tables used to organize the elements other than the Periodic Table? What are the advantages/disadvantages of each?