Questions tagged [elements]
A pure chemical substance consisting of a unique type of atom with a distinguished by its atomic mass.
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The “nose” of the periodic table [on hold]
My teacher said that on the periodic table there is a "nose" formed by Al, Zn, Ag, and Cd. She said that they are all fixed charged (+3, +2, +1, and +2 respectively), and said that if I write them in ...
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Crystal structures of heaviest nuclides' compounds
What is the heaviest element of the periodic table for which there is a compound whose crystal structure has been completely resolved by X-ray diffraction?
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What is so special about Beryllium (Be) and Magnesium (Mg)? [closed]
I am asking this because after studying periodic properties and trends of elements I have come to an understanding that these two elements ($\ce{Be \& Mg}$) are many of the time exception to the ...
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1answer
60 views
What element has good conductivity but is also brittle? [closed]
I'm confused by what element(s) can be identified to have these properties.
The following is text from my 2019-2020 Kaplan MCAT General Chemistry book under the metalloids section
Silicon (Si) has ...
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1answer
99 views
Why does period 3 of the periodic table contain 8 elements instead of 18?
Period 1 of the periodic table contains 2 elements ($1s^1$ and $1s^2$).
Period 2 contains 8 elements ($2s^1$, $2s^2$, $2p^1$, $2p^3$, ..., $2p^6$).
By the same argument, period 3 might contain 18 ...
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1answer
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Isotopes and elements [closed]
this is a gold bar. If we look at its structure, will we see that there are atoms that have a different number of neutrons (aka isotopes) (as far as I'm concerned, an isotope is an atom with a ...
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51 views
Predicting atomic weight and density of calcium [closed]
I have a question from school:
Assuming that the element Ca had not been discovered, predict using the properties of the known element surrounding Ca its own properties such as its atomic weight ...
0
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1answer
78 views
Why does zinc sulfide glow when hit by electrons? [duplicate]
In cathode ray tube experiment in order to check the direction of flow of electrons a hole was made in a note and behind it phosphorescent material zinc sulfide it was coated.
Why does zinc sulfide ...
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Electrolysis of a calcium salt in polar aprotic solvent
If i found a calcium salt that is soluble in acetone or ethyl acetate, which are polar aprotic solvents, and attempted electrolysis, what would happen? Since polar aprotic solvents are used in metal-...
0
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1answer
50 views
Doubt on Element [duplicate]
I read the definition of element:
Element consists of only one kind of atom and cannot be broken down into a simpler type of matter by either physical or chemical means.
Then as per definition, $\...
6
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1answer
856 views
“Estrontium” on poster
I was looking at a poster for an international chemistry olympiad. Its background contains some random elements as periodic table tiles.
One of them said "Estrontium." A google search returned ...
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1answer
122 views
What is the most common element in the human body? [closed]
I was wondering that since H2O was 66% of the human body, hydrogen would be the most. But apparently carbon is. Can someone explain that?
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Reasons for low melting point of gallium
J.D. Lee writes in Concise Inorganic Chemistry:
Gallium has an unusual structure. Each atom has one closest neighbor at a distance of 2.43 Å.
This remarkable structure tends towards discrete ...
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3answers
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Elements other than carbon that can form many different compounds by bonding to themselves?
My textbook says the following:
Unique among the elements, carbon can bond to itself to form extremely strong two-dimensional sheets, as it does in graphite, as well as buckyballs and nanotubes.
...
0
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1answer
118 views
Does dilithium exist? [duplicate]
Lithium has two electrons in $\mathrm{1s}$, filling the first energy level; and one valence electron in $\mathrm{2s}$. Could two $\ce{Li}$ atoms form a bond to create $\ce{Li2}$; like $\ce{O2}$ or $\...
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1answer
814 views
Two different electronic configurations for cerium
Depending on the textbook there are two different electronic configurations stated for cerium. On the one hand
$$[\ce{Xe}]\mathrm{4f^15d^16s^2}\quad$$
and on the other hand
$$[\ce{Xe}]\mathrm{4f^...
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0answers
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Why should I care about the highly radioactive elements after fermium? [closed]
After element 100, fermium, there are a bunch of highly radioactive elements like fermium, tennessine, and oganesson, and others. These elements are to radioactive to store, they will instantly ...
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1answer
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Does one atom of an element show the properties of a bulk of that element? [duplicate]
For example, does one atom of gold have a golden color?
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1answer
139 views
Is there an element with no liquid state? [closed]
I know this question might be dumb but, is there an element that will go directly from solid to gas, with almost no visible or no liquid state? Just a random curious question.
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What does it mean that an electron quantum numbers are n1= 4 - l1?
I'm trying to solve some exercises from the 2017 IChO, and the problem 6-A1 states that
in first ionization, an electron with the quantum numbers $n_1 = 4 - l_1$ is removed.
Now, I've never seen ...
4
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2answers
653 views
Chemical composition of seawater
Is it true that the sea water is composed of about $86\%$ oxygen, $11\%$ hydrogen and $3\%$ of minerals? The chemical formula of water is $\ce{H2O}$ (two hydrogen and one oxgen) that shows that the ...
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1answer
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Reactivity and its meaning
When we say that “potassium” is reactive, are we referring to a potassium atom or bulk potassium as in the solid metal? In other words does “potassium” refer to a type of atom or an agglomeration of ...
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It is possible to create any metal? [duplicate]
This question just popped up in head. There are many things which we are good at. We are good at:
constructions.
build stuff.
destroying things.
repairing things.
cleaning.
But I want also to know, ...
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1answer
90 views
Extracting sulphur from hot springs with medieval technology?
For the sake of a dungeons and dragons game. Could sulphur be deposited on/extracted from hot springs water through evaporation or other proess?
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1answer
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Is there a case when an atom of some element (e.g. carbon) does not have its expected number of protons (e.g. 6)?
Page 12 of the Study Guide for Campbell Biology, 11th Edition has the following question:
A carbon atom has 6 neutrons. How many protons are present in the nucleus of a carbon atom?
A. 12
...
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What is the chemical composition of the human body? [closed]
What is the average percent composition of each element in the average human body?
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2answers
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Atomic weight = expected weight?
The atomic weight of an element, is it accurate to say that another way to think of it is the expected value of that element's weight if we were to sample one at random from the environment?
Are man-...
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2answers
432 views
What is the true depiction of the periodic table?
Normally with the periodic table the lanthanide series is separated out because it's long and would make the table wide. I looked for an expanded version and found this:
I found it kind of strange ...
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1answer
138 views
Does the van der Waals force not affect the alkali metal 's trend of decreasing melting points down the table? [duplicate]
Melting and boiling points increase further down the halogen group, but they decrease further down the alkali metal group. I know that the former's trend has to do with the van der Waals force, but I ...
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1answer
53 views
Is there a blanket term for all variants (both nuclides and ions) of a chemical element?
I'm hoping to catalogue the various nuclides and oxidation states of an element but can't find a single term that describes them all, save for "chemical element variations". Is there a specific term ...
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1answer
366 views
Why is the number of protons and neutrons equal to the atomic mass rounded?
The mass number is defined as the NUMBER of protons and neutrons. Electrons aside, why does the number of protons and neutrons equal the atomic mass rounded to the nearest whole number? That would ...
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Why do all atomic masses have decimals if there are some elements that don't have isotopes?
I understand that the way to calculate the atomic mass is to obtain a weighted average of the masses of all the isotopes of an element. I also understand that there are about 26 elements that are ...
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Why are there only less than 120 elements out there ? [duplicate]
Why stop at 118 , Why aren't any more stable elements possible ?
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How to interpret detection limits
I am learning about different analytical methods such as Atomic Absorption Spectrscopy and Atomic Emission Spectroscopy and I'm having a difficult time understand how to interpret the detection limits ...
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1answer
74 views
Why atomic mass is taken in comparison?
The definition of atomic mass says that it is the mass of one atom of the element with respect to 1|12 of the mass of carbon-12 atom.
My question is that why there is need to compare the atomic mass ...
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2answers
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Gold Half-Life and the Longevity of Gold Curiosity [closed]
I was curious if the half life of Gold is 186 Days, then why does it 'Last forever' ... Wouldn't the ancient Egyptian gold artifacts be decayed to lighter elements by now like platinum? I know gold ...
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1answer
42 views
What transition metal ions form without oxidant in water pH 7? [closed]
I am not sure how many transition metals will ionize without oxidants, where could I learn this?
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Can halogens exist in their elemental state in nature?
Question 7 from the 2015 Australian Chemistry Olympiad was:
Which list below gives non-metals that can be found in their elemental form in nature?
(a) neon, phosphorus, fluorine
(b) helium, ...
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1answer
64 views
Library / function for computation of molecular mass / molecular weight in C
We are looking for a function to be used for computing the molecular mass / molecular weight / formula weight in C, either in a library or standalone. So far we have found the following ...
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0answers
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How did the atomic number and atomic mass of elements discovered? [closed]
Elements are small for our naked eyes.so,how did the discovery of its atomic number and mass number took place?
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1answer
241 views
How to test for halides without ammoniacal silver nitrate solution? [closed]
If I have an halide e.g magnesium iodide, how can I test what halide the compound contains?
I understand there is a method using silver nitrate and ammonia but what other methods are there?
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1answer
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How to experimentally measure number of protons or electrons in an element? [duplicate]
How can one measure the numbers of protons or electrons (the atomic number) in a substance?
Like if the element I examine is carbon I expect the result to be 6.
Preferable a simple experiment which ...
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0answers
282 views
Why are most atoms solids or gases but not liquids at room temperature? [duplicate]
Of all the elements of the periodic table, "most" elements with valences of four or less are solids, with most of these being either "metals" or "semiconductors."
On the right hand side of the ...
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1answer
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Why does it yield iron(II) chloride instead of iron when copper meets iron(III) chloride? [closed]
Complete the equation:
$$\ce{Cu + FeCl3 -> ? + ?}$$
I wrote $\ce{CuCl2}$ and $\ce{Fe}$, but it turned out to be $\ce{Cu}$ and $\ce{FeCl2}$. I really wonder why.
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1answer
456 views
Elements in the lanthanide and Actinide series [duplicate]
How many elements are there in lanthanide and Actinide series? My big doubt is does the 57th element Lanthanum and 89th element Actinium include in it?
In some periodic table the entire 57-71 is ...
0
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1answer
159 views
Is lanthanum a lanthanoid? [duplicate]
Is lanthanum classified as lanthanoids? If yes, then can somebody explain in detail why La has 6s2 5d1 as its electron configuration and Ce has 6s2 4f1 5d1?
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Elements which do not form oxides
I had thought that this question would be easy to answer but my searching has been unsuccessful in finding a clear answer.
For the metals, I expect that they all form oxides. Some very readily, e....
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Confusion over boiling point of gallium
I am completing a project on gallium, and I need to include its boiling point. I thought that this would be fairly simple to look up, however, it appears that different sources quote different ...
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1answer
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Have we found stable, super-heavy elements?
Have we found a stable super heavy element or created one in a lab, or are they still hypothetical?
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Pure substances have only one kind of atom
I read in a book recently that no substance is ever totally pure, even if we take great care to separate it from other substances.
And also that pure substances contain only one kind of matter.
But I ...
