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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Solubility of s block elements [on hold]

I am having a problem in understanding solubility of s block elements, of fluorides carbonates oxides hydroxides and chlorides. Pls explain me in detail, also why does hydrstion energy increases in ...
0
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0answers
16 views

How can we explain the exceptions in the periodic table? [duplicate]

I notice that chromium, molybdenum, copper, silver, gold, and roentgenium have an incomplete $s$ sub-shell and I'm usually told that it's because of the energy levels. However, I know there's got to ...
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1answer
37 views

Periodic Table Isotopes doubt

I recently studied that Mendeleev's periodic table had no place for isotopes and hence this came out as a shortcoming for the Mendeleev's table. But my doubt is, is the modern periodic table having ...
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1answer
66 views

Which is the most reactive element in the periodic table? [duplicate]

Which is the most reactive element in the periodic table? Is it francium, ceasium, lithium or flourine? It's really confusing.
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2answers
143 views

Why cesium considered most reactive element and not flourine? [closed]

Some people say Cesium is most reactive element. I thought it to be flourine as it is the element that reacts with almost all elements (except couple of inert gases). But cesium won't react many of ...
1
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1answer
87 views

Why isn't 4s1 electron of Chromium the last electron?

I know that to aid the symmetry of singly occupied orbitals one electron jumps from 4s orbital to 3d orbital thus giving Chromium the configuration 3d5 4s1. But my question is, when we're evaluating ...
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0answers
46 views

Relation of Boiling Point and Melting Point with the reactivity of an element

When we look at the trends of periodic table, there is an interesting correlation to be noticed. Along a period, when we look at the trends in reactivity of an element( Both due to electropositivity ...
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0answers
15 views

Coordination number of C in Methyllithium tetramer

According to Concise Inorganic Chemistry - J.D.Lee, the Coordination number of carbon in $Li_{4}(CH_{3})_{4}$ is $7$. But the structure of the tetramer is Doesn't carbon have coordination number $6$ ...
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0answers
24 views

table of expanded electronic structures of atoms

Where can I find the table containing expanded electronic configurations for atoms in periodic table, showing how outer electrons are distributed between different atomic orbitals? Well, i need just ...
0
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0answers
10 views

why is lithium the most electronegative element in its group [duplicate]

lithium has got the highest negative electrode potential in its group showing that it has the maximum tendency to donate an electron but still it has got the highest ionisation enthalpy
1
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2answers
138 views

What is the most common oxidation state of gold?

I had a test this morning which had the following question: What is the most common oxidation state for gold? +1 -1 +2 +3 My attempt: Since the electronic configuration of $\ce{...
3
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0answers
55 views

Why are there 3 columns in Group VIII of the Periodic Table?

I'm currently reading in-depth about the layout of the Periodic Table, and I wondered why the table has 3 columns in its Group VIII: As I understand, this is an old notation of the table, now ...
1
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1answer
42 views

What properties of later elements are predicted by scientists?

Though scientists have predicted up to element 172 (unseptbium) what properties do they predict any elements later on the extended periodic table may have?
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0answers
25 views

Is There any way to Easily Remember the Periodic Table [duplicate]

So for a test we have to memorize the periodic table. I was wondering if there was any easy way to remember it. Please Help.
1
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1answer
69 views

Why do some periodic tables have 18 groups while others have 8?

In school I have been taught about the periodic table with 8 groups, representing the number of electrons in the outer shell (with exceptions). But online almost all I can find is periodic tables with ...
0
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1answer
34 views

2nd Electron Affinity of halogens

I have seen questions regarding EA but they were all about the 1st EA so this question is not duplicate. I came across a statement which goes like "2nd EA of halogens is almost zero". How is this ...
0
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1answer
54 views

What is the correct order of chemical reactivity in terms of oxidising property for the following elements: F, Cl, O, and N

This is a textbook question. I am confused as to which factors i should consider while sorting out these elements. If I take electron gain enthalpy, then Cl should be greater than F, but if i consider ...
0
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0answers
13 views

Reverse trend in solubilty for alkali metals

In case of alkali metals, why does ENTHALPY OF FORMATION for fluorides become less negative down the group and opposite for chlorides, bromides and iodides ?
4
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1answer
81 views

Why can mercury(I) exist, but not zinc(I)?

Mercury shows variable valency while zinc does not. Its electronic configuration is $\ce{[Xe]\:4f^14 5d^10 6s^2}$. So it can donate the $\ce{6s^2}$ electrons and should only be able to form $\ce{Hg^2+}...
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1answer
51 views

Deviation of Ytterbium from general trend

What is the reason for deviation of ytterbium from the general trend of lanthanides in terms of hardness, melting point, density etc.?
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0answers
118 views

Anomalous Electronic Configuration of Thorium

The electronic configuration of thorium ($Z=90$) is $5\mathrm f^0 6\mathrm d^2 7\mathrm s^2$. But, according to the aufbau principle, the electrons should first enter the $\mathrm f$ subshell and not ...
2
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5answers
550 views

In the periodic table, why doesn't the 2nd row have exactly 2 elements?

Row 1: 2 elements Row 2: 8 elements Row 3: 8 elements Row 4: 18 elements Row 5: 18 elements Row 6: 32 elements Row 7: 32 elements In other words: 2, 8, 8, 18, 18, 32, 32 Why does the first row ...
3
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2answers
95 views

Why is the periodic table periodic?

I am not a chemist, but I am interested in Science in a general sense. Can anybody explain why the periodic table is periodic in nature? I would appreciate links for further reading.
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2answers
120 views

Why is Aluminum's 2nd ionization energy higher than Silicon's?

According to the periodic table trend for I.E. Silicon should have a higher 2nd ionization energy than Aluminum so I'm confused.
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0answers
21 views

Why is mercury in the copper group?

In various old inorganic chemistry manuals it seems to have been the practice to group mercury in with the "copper group". Why is this?
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1answer
253 views

How long the block starting with element 121 will be?

I remember from my chemistry classes that (after the initial irregularities) a new block of elements starts every two periods. After the initial s-block and p-block following it shortly, we have d-...
3
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1answer
417 views

Why does the boiling and melting point decrease as you go down group 1 and vice versa for group 7?

I used to think that because an alkali metal needs to lose one electron to complete its outer shell, when the atom increases in size (atomic radius), the electron would be easier to lose as the ...
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0answers
37 views

Chemical mixing question [closed]

What happens when Hydrogen is mixed with every chemical individually? What kind of reaction occurs? What happens when Lithium is mixed with every chemical individually? What kind of reaction occurs? ...
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1answer
63 views

Why do the chalcogens (Y) form YX4, YX6 but not YH4, YH6? [duplicate]

What is it about hydrogen that makes it different from the halides? What makes it only form di- and not tetra- or hexa- hydrides of the chalcogens?
3
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0answers
22 views

What explains the very high density of osmium and iridium? [duplicate]

Iridium with a density of $22.56$ g cm-3 & osmium with $22.59$ g cm-3. Data from their respective Wikipedia pages. Only these two naturally occurring elements have such a high density. I wish to ...
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1answer
165 views

What are inner core electrons and how do they influence chemical and physical properties?

There are six groups of p–block elements in the periodic table numbering from 13 to 18. Boron, carbon, nitrogen, oxygen, fluorine and helium head the groups. Their valence shell electronic ...
2
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0answers
19 views

How do I know the valence number by looking at the groups? [duplicate]

Groups say the valence number. For example Hydrogen is on group 1, has 1 electron on it's last and only level. So we can know the valence number on that are on the groups 1-2 and 13-18. But how am I ...
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1answer
68 views

A doubt about something related to elements above Feynmanium

Here I saw that if an element above atomic no 137 has to exist, it must have electron speed greater than speed of light. My question is , has this calculation been done keeping in mind Einstein's ...
2
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0answers
92 views

How do I model atoms with Moebius strips?

This question came to me while I was trying to model the list of elements (Mendeleïev), especially their masses and number of electrons. It came to my mind that it might be easier to model each ...
2
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2answers
3k views

Is iron the most stable element in the periodic table?

According to the binding energy per nucleon vs mass number graph, it is observed that iron-56 has the maximum value of binding energy per nucleon (8.75 MeV).It means that Iron-56 is the most ...
3
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1answer
65 views

Periodic table- quantum numbers

I have come across many questions like: "if electron had 3 spins (-1/2,0,+12) then what change will be there in the periodic table?", also sometimes " if the capacity of each orbital becomes 5 then in ...
2
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0answers
22 views

Families of some columns [closed]

From previous lessons, I know that column 1 are alkali metals, column 2 are alkaline earth metals, column 3 till column 12 are transition metals, column 17 are halogens and column 18 are inert gases. ...
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1answer
823 views

Memorizing polyatomic ions? Using Periodic Table

In my Chemistry course, we must memorize a list of common polyatomic ions. Is their an easy way of memorizing ions such as Sulfate $\ce{SO4^2-}$ by looking at just the periodic table. I listed the ...
8
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1answer
281 views

Periodic table group naming confusion - schools don't follow latest IUPAC?

In high school I am taught that Group 7 were halogens and Group 8 were noble gases, and Group 3 the boron group, Group 4 was carbon group, etc. Then when I looked up the groups, I found that noble ...
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0answers
18 views

Easy method to mug up periodic table? [duplicate]

Is there any way or shortcut to mug up periodic table elements in order. I always mix up the order and forget their atomic numbers, etc. I am now in class 12. So all elements are not required. Only ...
3
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0answers
157 views

Why is lutetium part of the lanthanide series?

I’ve been looking at the periodic table and began to wonder - why is lutetium part of the lanthanide series? Or, for that matter, why is lawrencium part of the actinide series? This isn’t readily ...
0
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1answer
478 views

Anomalous configuration for Palladium?

The p block elements generally have the general valence she'll configuration as $$n\mathrm{p}^{1-6}\,n\mathrm{s}^{1-2}.$$ Expected electronic configuration for palladium is $$\ce{^46Pd} = \mathrm{1s^2\...
6
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0answers
134 views

Which element has a greater second electron affinity, sulfur or oxygen?

I found a question asking the above which states that sulfur has a lesser second electron affinity than oxygen. But since the inter-electronic repulsion in sulfur is lesser, shouldn't it be willing to ...
8
votes
1answer
481 views

Confusion with the Periodic Table

The periodic table has 7 periods and they have 2,8,8,18,18... elements respectively from 1 to 7. But from what I understand, the periods each state the number of electron shells that the elements in ...
3
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1answer
1k views

Trend in the melting point down the group

We know the the atomic radii increase down the group. So less energy is required to pull the outermost electron as we go down the group and gradually melting points decreases down the group. The ...
8
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2answers
6k views

Is aluminium a metal or metalloid?

Aluminium is along the dark line of the Periodic Table and it is $p$-block metal. Is it metal or a metalloid? Why?
4
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1answer
833 views

Are the elements lanthanum and actinium considered to be in the d block or the f block of the periodic table?

Many periodic tables place lanthanum and actinium in the f-block of elements, for example, this periodic table from Los Alamos National Laboratory. However, this table from the Royal Society of ...
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1answer
14k views

Why are there peaks in electronegativities in d-block elements?

Looking at the Pauling electronegativities in the Periodic Table (below, from ChemWiki): Asides from the overall trend of increasing electronegativity across and up the Periodic Table (towards ...
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1answer
123 views

Periodic table groups - which grouping is “right”? [closed]

In searching online, I've noticed there are a lot of different ways to group the elements of the periodic table. Take mercury in the two tables linked below, for example: http://i.telegraph.co.uk/...
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3answers
650 views

Is there an abundance threshold of a 'synthetic' element for it to be considered natural?

I always (possible naively) thought that elements are either natural or synthetic, either one or the other. But, according to the Wikipedia page about Synthetic Elements, it states that: All ...