Electronegativity description

[bidiboom]

Hi guys,

These easy-to-pull-everywhere questions are killing me.. here is one:

"Electronegativity is a measure of the ability of an atom to draw valence electrons to itself."

The answer of the book is True.. to me False.. electronegativity is the ability of an atom to draw the electrons IN A MOLECULE.. the description in the question tells me effective nuclear charge, not electronegativity.. what do you think guys? Am I wrong?

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[Ssina]

Hi guys,

These easy-to-pull-everywhere questions are killing me.. here is one:

"Electronegativity is a measure of the ability of an atom to draw valence electrons to itself."

The answer of the book is True.. to me False.. electronegativity is the ability of an atom to draw the electrons IN A MOLECULE.. the description in the question tells me effective nuclear charge, not electronegativity.. what do you think guys? Am I wrong?

the answer sounds right i think... electronegativity is the pull of the nucleus on the valence electrons, whether the electrons are being shared in a bond (in a molecule) or not doesn't make a difference... in a molecule, the more electronegative atom has more of the electron density... so when bonding depending on the electronegativity difference, the bond could be covalent, polar-covalent, or ionic. (I've read that if the difference is more than 2 then it's ionic, btw 1.5 and 2 it's polar-covalent, and below 1.5 is just covalent... but the periodic table on the test doesn't have electronegativity numbers so doubt we have to know it)

and the answer I think is just trying to draw attention to the fact that this is due to Zeffective (well pretty much all of em.. electroneg, ionization e., radius, electron affinity, etc.)

 

[bidiboom]

Guys this is from Brown/LeMay/Bursten's Chemistry 10th Edition (from page:312 an excerpt as its written):

" ...Electronegativity is defined as the ability of an atom in a molecule to attract electrons to itself... "
(please notice that, its emphasized by italic words)

Which one is wrong now, textbook or testbook?

My comment:
Actually electronegativity is taken as a subject of perodic table, but I think to put the trend of attraction force of the atoms in a fictive bond, not real.. or in better words gradually its turning to ionic bond as we slide leftward in the periodic table.. so actually electronegativity in real world is something takes place in molecular substances, not in ionic.. the measure thats used for all kinds of atoms is effective nuclear charge, which accounts for the force attracting electrons..

Again depending on Brown/LeMay/Bursten's Chemistry (Glossary):
Effective nuclear charge The net positive charge experienced by an electron in a many-electron atom.

What do you think?

 

[Pisiform]

Hi guys,

These easy-to-pull-everywhere questions are killing me.. here is one:

"Electronegativity is a measure of the ability of an atom to draw valence electrons to itself."

The answer of the book is True.. to me False.. electronegativity is the ability of an atom to draw the electrons IN A MOLECULE.. the description in the question tells me effective nuclear charge, not electronegativity.. what do you think guys? Am I wrong?

"Electronegativity is a measure of the ability of an atom to draw Bonded electrons to itself.

^ That is a more accurate definition but valence electron is also correct because they are the ones that form bond.

 

[Erythropoietin]

don't think about valence electrons, but think about "pulling of electron density"

 

[Ssina]

I see your point, but I think the original T/F statement is rather a general statement about electronegativity and just because it doesn't say in a molecule or a bond doesn't mean it would be wrong.... I just think you have read way more than me in details about it so the statement seems inadequate (hence being the victim of the books lol), but for MCAT purposes (and right now that's the only real world I know of till Jan) it would be true...

Regarding Zeff, the definition sounds good to me, but I like to think of it as the pulling of electron density/valence electrons by the nucleus of an atom (which is implied in the statement net + attracting - electrons)... but a subtle info in there is the NET, because Zeff takes into account the pull by the protons on the electrons, the shielding by the electrons in the orbitals inbetween them, and i think even the repulsion of valence electrons on each other!

 

[askamsky51]

Caught a seriously silly mistake in my answer, feel free to ignore this post 🙂

 

[bidiboom]

Thank you very much people.. I got the point I think.. the important point is to catch the approach of the test and you helped me see this.. thank you all..
___________

Caught a seriously silly mistake in my answer, feel free to ignore this post 🙂

askamsky51, thats sweet 🙂

 

[Erythropoietin]

Thank you very much people.. I got the point I think.. the important point is to catch the approach of the test and you helped me see this.. thank you all..
___________


askamsky51, thats sweet 🙂

I think the most important thing to realize about electronegativity is the functional groups that are attached, and whether or not the protic hydrogen is directly bonded to the electronegative atom or not.

 

[BerkReviewTeach]

Not to add another point to the discussion, but while the textbook is technically correct that it's the desire for an atom to draw bonded electrons to it, the original question said "valence electrons" and did not specify whether those valence electrons were its own or from another atom. Given that valence electrons are shared between bonding atoms, the answer is not that far off.

The real problem I have is why a T/F question is being posted in the MCAT section, given that they give traditional four-choice MC questions on the MCAT. It's a different type of reasoning, even though it's based on an MCAT topic.

 

[bidiboom]

The real problem I have is why a T/F question is being posted in the MCAT section, given that they give traditional four-choice MC questions on the MCAT. It's a different type of reasoning, even though it's based on an MCAT topic.

Its not an MCAT question 🙂 its from SAT-Chemistry prep book of TPR.. I actually prepare for a European med school and because I am a non-trad of oolldd age, I have to both refresh myself and prove my knowledge about those prerequisite sciences, bio+chem+phys, albeit I had graduated long ago from a high school. I am a member of SDN and besides other forums I coincidentially found out that here there is a live forum about these subjects, and I joined 😳

 

[Erythropoietin]

Its not an MCAT question 🙂 its from SAT-Chemistry prep book of TPR.. I actually prepare for a European med school and because I am a non-trad of oolldd age, I have to both refresh myself and prove my knowledge about those prerequisite sciences, bio+chem+phys, albeit I had graduated long ago from a high school. I am a member of SDN and besides other forums I coincidentially found out that here there is a live forum about these subjects, and I joined 😳

Those T/F are tricky 😀 If you have EK 1001, they ask stuff similar to this, even though it takes a looong time to go over all that stuff.

 

[Ssina]

Not to add another point to the discussion, but while the textbook is technically correct that it's the desire for an atom to draw bonded electrons to it, the original question said "valence electrons" and did not specify whether those valence electrons were its own or from another atom. Given that valence electrons are shared between bonding atoms, the answer is not that far off.

The real problem I have is why a T/F question is being posted in the MCAT section, given that they give traditional four-choice MC questions on the MCAT. It's a different type of reasoning, even though it's based on an MCAT topic.

Totally agree, most of times feelslike a guessing game of finding the less debatable answer... def not use it to it yet!