Chemical bonding

blueftw SG

is chemical bonding in H2 chem easy? anyone has notes?

ThunderFbolt SG

easy or not depends on an individual's understanding, so difficult to answer that. you could just post anything you are not sure here.

blueftw SG

uhhh the lone pair lone pair > lone pair bond pair > bond pair bond pair one how to use to predict bond angle?

dkcx SG

You cannot predict the actual bond angle but u know that the order of their strength so lone pair lone pair replusion will push the bonds further away from them.

Eg ideal bond angle is 109.5 i think.

H2O has 2 bonding pairs n 2 lone pairs, since the lone pair lone pair replusion is stonger than lone pair bond pair and bond pair bond pair, it pushes the bond angle of water to 104 or something.

I would say in JC/uni, u will use that knowledge more for determining the shape of the molecule using Valence Shell Electron Pair Replusion (VSEPR) and the actual bond angle is less important for general use.

blueftw SG

what happens if we have NO2. 1 lone pair and 2 bond pairs?

dkcx SG

what happens if we have NO2. 1 lone pair and 2 bond pairs?

You just need to know NO2 molecule is bend shape base on VSEPR and the angle is not important. All i can say is the angle is less than 120

UltimaOnline SG

NO2 is an interesting molecule to draw. A couple years back, my student said that of the entire class, she was the only one who could draw it correctly in the exam, thanks to my tuition.

See if you guys (those currently in JC, or secondary school) are able to draw it correctly (without looking up Wikipedia).

Here's a check : if you drew it correctly, there's an unpaired electron present, and there is separation of charge (ie. formal charges within the neutral molecule).

dkcx SG

Not sure whether A's will study it but that molecule rather than saying has unpaired electrons or 1 single and 1 double bond, its more a resonance structure something like the benzene ring with no fix actual single or double bond.

UltimaOnline SG

One has to correctly draw the resonance contributors before one can combine them to elucidate the resonance hybrid. Therefore, it is correct and necessary for the student to work out that the valid resonance contributors have an unpaired electron and formal charges.