Questions tagged [electronegativity]

Refers to ability for an atom in a covalent framework to attract electron density to itself. Do not conflate with electron affinity, which is the ability of a lone atom (or molecule) to attract an electron to itself. Both are measured in joules/mole.

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8
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3answers
6k views

Strongest negative inductive effect group between trimethylammonium, ammonium and dimethylsulfonium groups

Which of the following group exerts the strongest -I effect? $\ce{-N(CH3)3+}$ $\ce{-NH3+}$ $\ce{-S(CH3)2+}$ $\ce{-F}$ My idea is that positive species exerts more -I effect than ...
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1answer
974 views

Why is carbon monoxide a monodentate ligand

Carbon monoxide has lone pairs on both the carbon and the oxygen atoms. However, I have never seen any complex where the oxygen atom or both the oxygen and the carbon atoms are the donors. I know ...
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3answers
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Percentage ionic character when electronegativity is given

What is the ionic character of a bond, $\ce{A-B}$, in terms of the electronegativities of $\ce{A}$ and $\ce{B}$ ($\chi_\ce{A}$ and $\chi_\ce{B}$)? I have been taught that the percentage ionic ...
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Why are noble metals more electronegative then most metals?

I was researching about electronegativity when I looked up what a graph of electronegativity within the periodic table is. And, this appeared. I scanned it, matching up everything I knew about the ...
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0answers
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Where will a H+ attack on 6-hydroxyhexan-2-one? [closed]

Where will a H+ attack on 6-hydroxyhexan-2-one? Protonation can take place either on the ketone or the alcohol. So where will it attack? In short, on which of the two oxygen atoms is electron density ...
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1answer
827 views

Why is hydrogen not very electronegative? [closed]

I looked at my reactivity series and I have just realized that hydrogen and carbon are both included in the series, even though they are non-metals. So why is hydrogen more electropositive than ...
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1answer
605 views

Why is fluorine one of the most electronegative atoms even though it doesn't have the largest effective nuclear charge?

Why doesn't electronegativity increase as the effective nuclear charge increases? Most atoms with a higher atomic number than fluorine have a higher effective nuclear charge. However, flourine is a ...
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3answers
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Is the inductive effect always measured relative to hydrogen?

Wikipedia has defined the Inductive effect thus: "In Chemistry and Physics, the inductive effect is an experimentally observable effect of the transmission of charge through a chain of atoms in a ...
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1answer
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Calculating the electronegativity of an element from bond dissociation energies

Calculate the electronegativity of fluorine from the following data: $$\begin{align} \text{BDE}(\ce{H-H}) &= \pu{104.2 kcal/mol} \\ \text{BDE}(\ce{F-F}) &= \pu{36.6 kcal/mol} \\ \text{...
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1answer
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Structures for NO+ (Nitrosonium)

There are two possible structures for Nitrosonium : In the first structure, there is a +1 Formal charge on Oxygen, whereas, In the second structure, there is a +1 Formal charge on Nitrogen. Q. ...
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1answer
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Is there a mathematical formula for electronegativity?

If we lost all the numerical values we have for the electronegativity of elements, is there any mathematical formula that can be used to re-calculate them based on proton (and neutron) numbers alone? ...
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1answer
9k views

Relative strengths of hydrogen bonds

Order of hydrogen bond strength: $\ce{O-H...N}$ > $\ce{O-H...O}$ > $\ce{N-H...N}$ > $\ce{N-H...O}$. Why is that so? According to me $\ce{O-H...O}$ should have the maximum strength while $\...
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1answer
484 views

why fluorine and oxygen have different behaviour towards electron gain enthalapy and electronegativity? [closed]

I have seen following definitions in my textbook: Electron gain enthalapy may be defined as enthalpy change taking place when an isolated gaseous atom of the element accepts an electron to form a ...
14
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1answer
1k views

Why is the bond dissociation energy of C-H bond higher than that of a N-H bond?

Looking at a chart of BDEs (bond dissociation energies) regarding elements bonded with hydrogen, the general trend seems to be that the BDE increases as we go to the top and to the right. This can be ...
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1answer
5k views

Relationship between dipole moment of a molecule and electronegativities of constituent atoms

I want to know if I can calculate the dipole moment of a molecule given the electronegativity values for the atoms comprising it. I think that dipole moments determine the polarity of molecules, so ...
5
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1answer
795 views

Using electronegativity and atomic size to compare acidity of cysteine with serine

In proteins, the alcohol group of serine is generally more difficult to deprotonate than the thiol group of cysteine. Serine and cysteine respectively: In the literature, the explanation given is ...
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0answers
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Effect of Electronegativity on Bond Angles in NH3 and NF3 [duplicate]

I am reading a book: Concise Inorganic Chemistry by J.D.Lee (Fifth Edition) In the chapter-The Covalent Bond, the author says: $\ce{NF3}$ and $\ce{NH3}$ both have structures based on a tetrahedron ...
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1answer
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How does an atom's electronegativity change as it becomes more negatively charged?

I had a question about the carbon atom specifically. Carbon has 4 valence electrons, with electronegativity 2.55 (approx). If I was to fire electrons at the carbon atom, each carbon will occupy up to ...
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2answers
432 views

Why do atoms have electron Affinity? [duplicate]

Atoms are stable so how can they pull electrons i.e how do they have any electron affinity at all?
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1answer
209 views

Will there be change in electronegativity difference in C-O and C=O?

Is there any change in EN difference in C-O and C=O. If yes, why? Does EN difference change if its bond is changed to single, double, or triple?
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1answer
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Why does C=O have a larger dipole moment than C-O?

Why does $\ce{C=O}$ have a larger dipole moment than $\ce{C-O}$? According to me, dipole moment directly depends upon bond length and electronegativity difference. In $\ce{C=O}$ and $\ce{C-O}$, (I ...
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1answer
49 views

What measures of the dielectric constant mark whether the solution is ionic, polar and nonpolar? [closed]

At what numerical values of ε, then what organic compounds if any mark these thresholds. How is that only for a vacuum has ε=1? This is absolute lowest limit?
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2answers
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Allred-Rochow vs Pauling Electronegativity scale

While observing the trends in electronegativity of the elements, I found a discrepancy between Allred-Rochow and Pauling scales. In Pauling's scale, chlorine is the third most electronegative element (...
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1answer
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Intramolecular or intermolecular?

I am extremely confused about these types of forces. Some websites state that the forces in the covalent bonds of carbon dioxide are inter. Other websites say they are intra? Also, some websites say ...
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Change of electronegativity of carbon atom by changing substituents

I was wondering how electronegativity and charge of carbon atom is affected by switching the substituents. For example what will be the difference in electronegativity of carbon atom in CF3, CCl3, ...
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1answer
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Carbonyl carbon electropositivity?

Is the carbon in a carbonyl functional group electropositive? I had a professor tell me so, but I immediately refuted him, because he defined electronegativity earlier as the ability to stabilize ...
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Why don't I get the same value of percentage ionic character of a particular molecule from different equations?

About the ionic character of a polar covalent compound Pauling gave two equations as [1-$e^{.25(x_a - x_b)}] $% [18$(x_a-x_b)^{1.4}$]% Hanary and Smith gave the equation [$16(x_a-x_b)+3.5(x_a-...
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2answers
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Bond angles in NH3 and NCl3

The bond angle in a molecule is inversely proportional to the electronegativity of the surrounding atom if the central atom is same. This also happens with $\ce{NH3}$ and $\ce{NF3}$, as bond angle in $...
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1answer
618 views

Why do some elements with high electronegativity exhibit metallic properties?

Metals typically have low electronegativity, which makes them form ions easily and prefer making metallic bonds to covalent. However, some of them seem to disprove that. Take, for example, gold, lead ...
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1answer
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What is the reaction mechanism between a basic oxide and an acid?

For instance in $$\ce{ Li2O (s) + 2HCl (aq) -> 2LiCl (aq) + H2O (l)}$$ I am wondering why the $\ce{Cl}$ displaces $\ce{Li}$ .I figure that oxygen is negatively charged as it pulls the electron from ...
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3answers
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Why is the boiling point of alkyl iodide is more than alkyl fluoride?

As far as I know, more the polar character of the organic compound, more will be the energy required to break the bond and thus more boiling temperature. Here in this case, $\ce{R-F}$ is more polar in ...
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1answer
231 views

electronegativity and hydrogen bonding [duplicate]

I have a basic idea why, but can someone just confirm, why chlorine isn't able to hydrogen bond despite the fact that it has the same electronegativity value as nitrogen.
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Do some electrons transfer if I connect with a conductor 2 solid pieces of 2 different elements with different electronegativity? [closed]

Making some researches to answer my last post, I found this article. It explains that when a piece of zinc and a piece of copper are connected with a conductor, since copper is more elctronegative ...
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4answers
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Which molecule is more acidic: CHF3 or CHBr3?

I know that fluorine is more electronegative than bromine. However, because of the size of bromine, it is more stable with a negative charge. In the case of $\ce{HF}$ vs. $\ce{HBr}$, to me, $\ce{HBr}$ ...
2
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1answer
358 views

Determine most electronegative element based on successive ionization energy data

X, Y and Z are three unknown elements whose first 5 ionization energies are given below. Which of the 3 is the most electronegative?$$ \begin{array}{|c|c|c|c|c|c|}\hline &\text{IE}_1&\text{IE}...
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1answer
403 views

Which is more electronegative: hydrogen or astatine?

Which is more electronegative - hydrogen or astatine? I'm a bit confused because my teacher taught me that for an atom to be electronegative it has to be on the top of the periodic table and/or on the ...
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2answers
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Directional nature of the acetamido group in electrophilic substitution reaction

Here, in $\ce{CH3CONH2 -}$ group, the nitrogen has a lone pair and can thus activate the benzene ring along with having an ortho-para directive effect in the following manner: However at the same ...
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2answers
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What is the reason for strong acids/bases dissociating in water?

I have read that the actual definition of a strong acid is one which will fully dissociate in water, so please do not turn the problem on its head when answering. It is also my understanding that ...
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2answers
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Why electronegativity instead of electropositivity

When I learnt about polarity, I always come to the term electronegativity and always use the electronegativity chart. However, when I studied further, they have the word electroposivity. So, I've ...
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1answer
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Why in SN1 reaction the order of reactivity of alkyl halides increases from fluorine to iodine?

In $\mathrm{S_N1}$ mechanism alkyl halides need to be ionized, so wouldn't it make more sense if alkyl fluoride reactivity were the most, since it is the most electronegative element?
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3answers
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Why does electronegativity increase as effective nuclear charge increases?

I know that electronegativity is the ability to attract shared electrons and that effective nuclear charge is the pull of the nucleus on outer electrons based on my notes. But I'm not really sure ...
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1answer
2k views

What is boron classified as a electronegative element and a electropositive element? [closed]

What is boron classified as a electronegative element or a electropositive element? Is electronegativity a relative concept ? Why is it that sometimes we treat Boron as an electronegative element ...
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4answers
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Why does NF3 have a smaller bond angle than NH3?

I've already read many answers about the reason why $\ce{NF3}$ has a smaller bond angle than $\ce{NH3}$ , but I can't seem to understand them. Here's my understanding of the situation: $\ce{NH3}$: ...
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2answers
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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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0answers
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Is there any mathematical formula for electron affinity and ionization potential?

I already know about the mathematical formula for electronegativity, but it requires the ionization potential and electron affinity. How can I can easily calculate the ionization potential and ...
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1answer
4k views

Galvanic cell using NaCl, Cu and Zn, why does it work?

Got a paper due tomorrow in chemistry, and my friends and I are totally stuck on this: Basically we mixed some regular salt (NaCl) into a glass of water and stuck a zinc nail and a copper nail into ...
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6answers
23k views

Why is carbon dioxide nonpolar?

I understand that polarity corresponds to an electronegativity difference and that the larger the electronegativity difference, the more polar the bond. However, I have read that carbon dioxide is ...
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0answers
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Is it possible to calculate electronegativity of surface atoms?

As the title asks, is it possible to calculate the electronegativity (EN) of specific atoms on extended surfaces (slabs), more specifically using computational methods? There are a few issues here I ...
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0answers
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How to identify where a bond will break and where a bond will form (acetals)

In the following reaction: The $\ce{H}$ from $\ce{ROH}$ joins the $\ce{O}$ in the carbonyl. So the Alcohol breaks at the bond between the $\ce{R'O}$ and the $\ce{H}$. How do I know this occurs, ...
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0answers
332 views

Electronegativity difference value [closed]

What is the exact electronegativity differece value of determinig whether a compound is ionic or covalent? Is it 1.7 or 2.1?