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.
260 questions
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Periodic Table Group 3 Period 6, 7 [duplicate]
I am studying Periodic Table and have doubts in the group 3 (III-B) periods 6 and 7.
If f-block is not a part of d-block, then why so they place inner transition metals in the boxes of group 3 ...
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Classification of elements into strictly anions and cations [closed]
I want to know elements of the periodic table which are strictly cations and anions, unlike H, C, Si, Ge, As, Sb, At,etc which can be both (i.e. amphoteric elements). Also, kindly add to this list of ...
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Question about Normal , Transition and Inner Transition Element?
My teacher recently taught us about Normal Elements ,Transition Elements And Inner Transition Elements.
He told us that If Outermost shell is incomplete then the element is normal element ,If both ...
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Are homoatomic molecules like ozone, graphite, diamond considered as elements [closed]
While researching I have found two definitions for element.
First, elements are pure substances that consist only one type of atoms. According to this O2, O3, Diamond and in short all allotropes are ...
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Why does the 1st ionisation energy decrease from the 9th period to the 10th period
I’m currently looking at the ionisation energy chart within my chemistry textbook and while I know that there are not really meaningful periodic trends within transition metals, generally the ...
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Naming of Mendeleev’s predicted elements- ekaboron and ekaaluminium [duplicate]
I’m studying the evolution of the periodic table as part of my school syllabus(CBSE class 11th). I have a doubt in the naming of predicted elements in Dmitri Mendeleev’s periodic table:
From what I’ve ...
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Upon what does the half life of a nuclide depend on? [duplicate]
Nuclide half-lives seem to be apparently random, except for the fact that heavier elements are typically radioactive and lighter ones stable. Is there any factor that can predict the half life of a ...
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2
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Electronic Configuration of Atomic Numbers 20-28 and 29 (Calcium - Nickel) and Copper [closed]
I have always been confused as to why elements of atomic numbers 20-28, i.e., Calcium to Nickel have 2 valence electrons in their outer shell. Starting from Potassium, why is one electron present in ...
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Why don't Zn, Cd, Mn and Hg have more than one metallic structure at normal temperature, while other d-block elements do?
It's been given in my book, that "With the exceptions of Zn,
Cd, Hg and Mn, they have one or more typical metallic structures at
normal temperatures."
But, why this exception?
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2
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Are there common/trivial/archaic names for any of the periods of the periodic table?
There are "common names" for all of the s and p block groups of elements (alkali metals, alkaline earth metals, icosagens, crystallogens, pnictogens, chalcogens, halogens, noble gases) (...
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Are periods the horizontal numbers on the periodic table and groups the vertical numbers?
I am writing this post so that I can ensure for my upcoming SUC3U0 (Chemistry, Grade 11) course test of nomenclature is correct. It's a Review of my Grade 10 General Science Course.
My teacher stated ...
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Why does Cr have higher melting point in the 4 period among the transition metal? [duplicate]
There is a lot of answer stating that the low enthalpy of atomisation in Cr is due to the reason of partially filled d orbital, thus having extra stability. This makes the orbital more attracted ...
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Why is there a non-uniformity in even the reasons that explain exceptions in the trends in chemistry? [closed]
I have been studying the periodic table and several properties of atoms like the Ionization Energy, Atomic Radii, Electron gain enthalpy, Electronegativity etc.
Now, each property has somewhat of a &...
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Why are p orbitals most important for stability? [closed]
Is there nice way to see/show/derive why p orbitals are so important for stability? Or asked differently: Why are elements with filled p orbitals on the right side of the periodic table? Why aren't ...
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2
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What words can I use to differentiate between cases where two atoms are of the same element versus when two atoms are of different elements?
I am writing my thesis, and usually I'm quite good with picking the right words for specific phenomena, yet I am having trouble finding the right words for this specific circumstance. I am trying to ...
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How did Mendeleev improve on the Newland's table?
I understand that John Newland’s law of octaves was ridiculed by the scientific community as his table failed to work past calcium. I'm trying to understand how Mendeleev’s table improved on this.
On ...
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2
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In mercury the o shell has 18 electrons but we know that second last shell cannot have more than 8 electrons? [closed]
The last shell has 2 electrons and the second last has eighteen electrons. Byt we know that second last shell cannot have more than 8 electrons. Then how is this possible. Please explain in simple ...
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548
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Why wavelength of Rubidium flame test(red violet) is more than Lithium(crimson red)
My teacher show this table from my book
Here, you can see Red violet wavelength is more than Lithium, which is against order of visible light which increase according to acronym 'VIBGYOR'
According ...
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2
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Is the periodic table ordered by bonded atoms and does that change the electron configurations and ordering? [closed]
In my book (Mortimer, The Basic Knowledge of Chemistry) the electron structure of the elements is introduced, there the relative energies of the atomic orbitals are shown:
1s < 2s < 2p < 3s &...
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Lower melting points of zinc, cadmium and mercury
I am aware of the fact that d-block elements like zinc, cadmium and mercury have lower melting points than other d-block elements. Also I am aware that these three metals have a fully filled d shell.
...
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Is "pentel" a real chemistry term?
Allegedly "pentel" is a synonym for "pnictogen," that is, an element of group 15, the nitrogen group. However, I have not been able to find any sources to support the existence of ...
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Why does berkelium have two electronic configurations?
J.D. Lee Concise Inorganic Chemistry, Appendix E: Electronic Structures of the Elements [1, p. 601] provides two electronic configurations for berkelium:
$$
\ce{Bk}\quad
\begin{cases}
[\ce{Rn}]~\...
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Why are there so many metals in the periodic table?
Brief Background: I was studying about the 'classical electronic configuration' of the first 20 elements of the periodic table today and was bewildered by the fact that there are an equal number of ...
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Why ionization energy of Thallium is higher than that of Indium?
I just normally calculated the effective nuclear charge (Zeff) for thallium and Indium from Slater's law, and I found it same for both! That is 5.(If you want calculation for answering or correcting ...
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1
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Confusion regarding 1st and 2nd electron gain enthalpy
$\ce{O}$ has the 1st electron gain enthalpy $\pu{-141 kJ mol-1}$. $-ve$ value implies that energy is released when electron is added to an isolated atom. This also means that if $\pu{141 kJ}$ energy ...
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If sulfur is directly below oxygen on the periodic table, why isn't SO the most common sulfur oxide? Instead of third, behind SO2 and SO3? [closed]
Chalcogen like oxygen and sulfur want to 'grab' (or share) two electrons to get to eight, if possible, or maybe 'give up' (or share) six, if necessary, to again get to eight... Right?
So, why is ...
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Why is scandium not in Group 13 despite being once called "eka-boron"?
When drawing up the Periodic Table, Mendeleyev famously predicted the existence of then-unknown elements such as "eka-boron", which we now know as scandium.
However, in the modern Periodic ...
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In school, I learnt that Potassium is the most reactive element in the reactivity series. I thought it was Francium?
In school, I learnt that Potassium is the most reactive element in the reactivity series. In the periodic table, the further you go down the more reactive the elemnt is. If this is true, then shouldn'...
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Melting and boiling point of transition-metals, primarily for the groups of Cr and Mn [duplicate]
The NCERT Chemistry book for Grade 12 writes
The high melting points of these metals are attributed to the involvement of greater number of electrons from $(n-1)d$ in addition to the ns electrons in ...
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Just how accurate is this XKCD comic about building a real-life periodic table with cubes made up of each element?
I was reading the book “What If?” by Randall Munroe and this part was very intriguing to me. He answered the question in the title and I was curious if his answer was realistic, and if not, which ...
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Confusion regarding trends in modern periodic table [closed]
We know that atomic radius decreases along a period and increases along a group. (Same goes for metallic character)
But if we take 2 elements A & B(A is at somewhere in the top and left in ...
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Lead vs Carbon Properties
Lead and carbon are part of the same group on the periodic table, so they have the same number of valence electrons. However, their chemical and physical properties are dramatically different. But why ...
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Why an atom is more stable when only sublevels s and p are full?
Supposedly when explaining electronegativity and stability of an element, they tell you that it is more stable if the last level is full. That works up to the third period, but after transition ...
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How do the odd proton-number elements originate?
I have a question about the origin of the odd proton-number elements in the periodic table, please.
As it is generally thought that the big bang produces hydrogen first, and then hydrogen combined to ...
user120456
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1
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Is there a canonical variable for period and group?
For example, "Z" is the standard symbol for atomic number. I'm writing a manuscript that uses the group and period of elements within some equations, and so far I'm just denoting them as $G_{...
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1
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Why does $\mathrm{NO_3}$ have charge $1-$? [closed]
I'm given the following problem:
Write the molecular equation for the reaction $\mathrm{Iron\;(III)\; Nitrate\; and\; Sodium \;Phosphate}$
I begin by attempting to determine the empirical formula of ...
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calculation of relative atomic masses in the periodic system [closed]
If I now want to calculate the relative mass of c-13 based on the definition m(c-12) = 12amu, I need the q/m values of c-12 & c-13, where do I find these (I've looked everywhere on the internet)? ...
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Does fluorine have 5 or 7 active valence electrons?
In a paper on chemical periodicities of elements, Cao et al. show the number of valence electrons in a periodic table (https://doi.org/10.1515/pac-2019-0901). Apart from Boron and Aluminum shown as ...
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How to know the number of valence electrons of f-block elements? [closed]
I kinda know how to get the valence electrons for s/p/d- blocks but i don't know about the f-block.
Wikipedia says that valence electrons for f-block is ns + (n-1)d + (n-2)f, so is it true? If so can ...
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How to know the group number from the ionization energy?
The successive ionization energy of the first four electrons of a representative element are $\pu{738.1 kJ/mol}$, $\pu{1450 kJ/mol}$, $\pu{7730 kJ/mol}$ and $\pu{10500 kJ/mol}$. Characterize the ...
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atomic structure - why only hydrogen be separately written in periodic table [duplicate]
The other
exception is hydrogen. It has only one
s-electron and hence can be placed in group 1
(alkali metals). It can also gain an electron to
achieve a noble gas arrangement and hence it
can behave ...
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Naming of the chemical elements and original sentences by the discoverers
Does anyone recall a printed or an online compilation where the names of all the chemical elements are listed along with the original sentence, from a research paper, containing the name of the ...
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Do Ions with less stability have less energy of ionization than those who are stable?
Problem. I've come up with the strange example of the third energy of ionization of both $\pu{Mg}$ and $\pu{Al}$, the standard logic that is to be applied on any problem of "which element has ...
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What would happen if electrons were spin-1?
We were speaking about this in class, but I can't understand it quite well. What would happen if (hypothetically of course) the allowed $m_s$ values were $-1$, $0$ and $1$? What impact does this have ...
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Doubts regarding Mole concept and Avogadros number [closed]
So I am really confused about simple topics like mole and Avogadro
Here is my oversimplified view
So mass of 1 atom of elements in grams was not in whole numbers and it was difficult using em for ...
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Why is effective nuclear charge used to explain the periodicity of size of atoms and ions?
Why is effective nuclear charge used for explaining the periodicity of size of atoms and ions, even though radius depends upon many other factors?
The size of $\ce{Na+}$ is smaller than that of $\ce{...
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Does the Atomic Mass listed for each element on the periodic table reflect the relative abundances of their isotopes on Earth? Or in the Universe? [duplicate]
Somehow, I cannot find a site or book or paper explaining exactly how the average atomic masses for the elements on the periodic table are weighted....
I posted a question either here or on Physics S....
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Relation between Ionization energy and reactivity
So I was learning about the periodic table where I came across the topic of ionization energy. As a general trend the Ionization energy decreases as we move down a group with a few exceptions such as ...
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1
answer
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What is the name for the relationship between two elements in the same group?
I'm looking for a specific term which can be used to describe two elements in the same group of the Periodic Table. This would be useful since elements in the same group tend to have similar chemical/...
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Spontaneity and nature of attack of fluorine gas on aluminum
What is the nature of the reaction of attack of fluorine gas on aluminium metal? Is it spontaneous in nature?
I have studied reactions of halogens on aluminium, but it had no information about ...
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