The periodic table is a systematic arrangement of the known chemical elements in order of atomic number. The elements are arranged in groups on the basis of similarity in chemical and physical properties.

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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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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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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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Why lanthanides and actinides are shown separate from standard periodic table layout?

In standard periodic table layout , all the elements upto 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 this ...
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Classifying atoms as metals or nonmetals based on the periodic table [closed]

The electron configuration of the outer shell of four atoms are: $X: 3s^23p^3, Y: 6s^26p^3, Z: 3s^23p^4 T: 6s^26p^4$. I don't know if these atoms are metal or nonmetal. Please classify the four ...
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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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The formula for finding the percentage of isotopes in an element's atomic weight?

In my class my teacher showed us how to find it, with a method, but he didn't really state the formula. I conjured up a formula from what I observed and it works. Here it is: $$ \frac{i_1x + ...
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Why does sulphur exist as $S_8$ molecule? [duplicate]

Sulphur belongs to the same group as Oxygen. Then why Oxygen exists as an $O_2$ molecule while Sulphur exists as $S_8$ molecule? What's the Chemistry behind it?
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105 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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139 views

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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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 ...
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206 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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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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49 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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310 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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187 views

How many p-orbitals are there in each period?

The question is this: How many p-orbitals are there in each period? a) 1 b) 3 c) 5 d) 7 e) 14 I take this to mean "how many p-orbitals are there in each period of the periodic table?" Looking at ...
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97 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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189 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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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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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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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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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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171 views

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

The question is pretty much the one in the title!
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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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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 ...
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314 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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Is At a non metal or a metalloid?

Is Astatine a non metal or a metalloid? A metalloid is an element which exhibits some of the properties of a metal as well as those of a non metal.
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Hydrogen - its place 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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109 views

Periodic Trends

I was just wondering if anyone could help me by telling me the trends and why that trend exists in the periodic table for the following: Atomic Size Ionization Energy Metallic Character Positive ion ...
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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 ...
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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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197 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 ...
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225 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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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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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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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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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 ...
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386 views

Is there a similar characteristic of the Lanthanide Contraction in the other transition metal groups?

Basically, does this 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 lower atomic radii occur. ...
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What are alternates 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?
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Brittle d-block metal trend

I remember seeing a periodic table that had the top-left corner of the d-block shaded and marked as "brittle". If I recall correctly, the elements were $\ce{Sc,Ti,V,Cr,Mn,Y,Zr,Nb,La}$. I think (Sorry, ...