Hydrogen Bonding

[Nayra Gharpetian 3F]

What specific characteristic do N, O, and F have that allow them to hydrogen bond with H? Is it just because they are highly electronegative?

[Hannah Lechtzin 1K]

They're highly electronegative, so when they are already covalently bonded to hydrogen (like in H2O) the electron repulsion between hydrogen and N, O, or F results in the N, O, or F exhibiting a slight negative charge. This causes them to be attracted to slightly positive hydrogen atoms, thus forming a hydrogen bond.

[Megan Lu 3D]

Hi! To my understanding, it is the combination of electronegativity and size that allow N, O, and F specifically to form hydrogen bonds. F, O, and N are some of the elements with the greatest electronegativity, and they are also unique in that they have relatively small sizes compared to other also-electronegative elements (ex: Cl), which may feature low electron densities due to their larger sizes.

[Jonathan Banh 1G]

H-N, H-O, and H-F bonds are typically associated with hydrogen bonding due to how there exists a great electronegativity difference between H and the respective atoms. Thus, H will tend to be slightly positive while N, O, and F will tend to be slightly negative. This relationship is what facilitates the occurrence of hydrogen bonding in substances with these kinds of bonds.

[Aydin Karatas 1F]

On top of the fact that N, O, and F are very electronegative, which does cause them to have a slightly negative charge, for H bonding to occur, the H must also be slightly positive. H in methane can't hydrogen bond because there isn't a sufficient electrostatic difference between C and H, but H in water can because there is a significant electrostatic difference between O and H. This positively charged H will occur if H is covalently bonded to an N, O, or F.

Hope this helps.

[Joshua Chung 2D]

When an H atom is bonded to a N, O, or F atom, it causes a notable electronegativity difference due to the strong electronegativity of N, O, and F. Thus, the present partial charges allow for the formation of a hydrogen bond.

[Alex Benson]

Hi! I believe that N, O and F are able to have hydrogen bonds is because they are highly electronegative. This is because N, O and F usually have a negative charge within molecules, whereas H has the positive charge.

[Jason Knight - 1F]

N, O , and F are all electronegative and small relatively, and on the other hand the H atom is highly positive which allows for successful hydrogen bonding.

[Jaden Kwon 3C]

F, O, and N have very high electronegativity differences relative to H which leads to a strong polar covalent bond, or a hydrogen bond.

[Arnav Saud 2C]

N, O and F are all small and highly electronegative. This can be seen through the trends on the periodic table.

[Kandyce Lance 3E]

Since ice is less dense than water, it floats but in alcohol it sinks so is that because alcohol is more dense than ice and also alcohol also takes a very long time to freeze, is this because of the density, or it it caused by hydrogen bonds?

[Anthony_Sandoval_1D]

F, O, and N are small and are electronegative whereas H is positive.

[apurva-3E]

They are highly electronegative

[Chenning Yang Dis3l]

N, O and F are all small and highly electronegative, while hydrogen is suitable for strong covalent/hydrogen bond.