Does Electronegativity Vary in Different Bonded Atoms?

[nandinitri]

i wanted to ask this….
1. if an atom forms a bond with some atom of different element,say
C-O ,then since O attracts elec more ,can we say tht it now it has less electronegativity compared to only O?
2. in a tertiary carbon why do electrons get pushed towards the central C,is it because of the presence of some other group,say OH or +ve charge(carbocation) or would it still occur if they were not attached…??(cud it be bcoz of the slight electronegativity difference between C and H??)

 

[nandinitri]

someone please help!

 

[keisu]

I don't know if I've interpreted your question correctly but,

1. yes, C has less electronegativity than oxygen. Remember, the electronegativity trend increases as you go up and to the right of the perioid table..so an arrow towards fluorine.
ch3
2. Tertiary carbon, ch3-c-ch3, wouldn't this molecule be nonpolar?
ch3

since there isn't really an electronegativity difference big enough..why would the electron density be pulled by the central carbon??

 

[rktpro]

Isn't it C which attracts more electrons in C-O ?

 

[keisu]

No, oxygen attracts more electron density...it's more electronegative than C

 

[calculusian]

No, oxygen attracts more electron density...it's more electronegative than C

absolutly right as dipole of oxygen more than carbon!

 

[nandinitri]

thanks all of you...i think one mistake i was making was you can't really tell the electronegativity in an element ...it happens in a bonded molecule ...(in my 1st question!