[Mercedes Benzene]

Hmmm.... how to explain this...
I'll try.

What is the total number of atomic orbitals possible at n =3?
I thought the answer would be 5 but it's actually 9, can someone explain why there are 9 orbitals?

Okay, if n=3, then it means that there are 3 azimuthal quantum values (l): 0, 1 and 2, as given by the statement 0 <= l < n (l = n-1).
Anyway, l = 1 includes 1 type "s" orbital. l = 2 includes 3 type "P" orbitals. l = 3 includes 5 type "d" orbitals. If you add the total number of orbitals up (1+3+5), you get 9.

How many electrons in an atom can have the following sets of numbers: n= 4 and m(subscript l)= +2/-2? The answer is 8 while I thought it was 14. Can someone also explain this?

Hmmm... again, it's rather hard to explain.

Basically, there are 4 orbitals that fulfil those requirements (+2/-2) when n = 4. There are m=+2/-2 orbitals in the l = 2 subshell, and m=+2/-2 orbitals in the l= 3 subshell. (4*2) = 8.

I hope this helps!

[XrayBravoRomeo]

I have a question regarding hydrogen flouride. The electronegativity difference between them is 1.9, so it should be an ionic compound right?

However, my book says that an ionic compound is when a metal, and a non-metal bonds together, and H and F are both non-metals.

I also read that HF is an acid, and it has a hydrogen bond. Like ammonia (NH3) and water. But none of them has ionic compound between the atoms? They have polar covalent bonds?

Long story short:
What bond is between the atoms in HF?

Sorry if this was an obvious question, I just started chemistry

Thanks in advance

[learnin to learn]

actually it is a pretty good question! and I for one have no clue!

[Jay-qu]

I think it is a covalent bond. It is an acid, moderately strong in water but extremely stong in higher concentrations. It will hydrogen bond also.

[Mercedes Benzene]

Hydrogen Fluoride is indeed an ionic compound. The hydrogen counts as a "metal" do to its +1 charge. Hydrogen needs to lose one electron. Fluorine needs to gain one. They don't care that they're both gasses.
I'll also note that Hydrofluoric acid is considered a weak acid and does not completely dissociate in water. This characteristic may make it seem more like a covalent molecule.

[hallenrm]

Chemical bonds are like shades of colour in real life, there are seldom a perfwct white or black, they are shades of gray. Coming back to chemical bonding, it is just a concept to describe the sharing of electrons between the atoms in a molecule; if it is more inequitable, it is termed ionic and if it is equitable it is termed covalent, just like poor and rich or for that matter capitalism and socialism.!

[XrayBravoRomeo]

Thanks for the replies

[Michaelangelica]

Being a mad gardener I would really like to understand this. "Caton exchange Capacity"
But I can't
I have NO chemistry.

I don't understand all the - and + tives.

Can anyone help?
http://syllabus.syr.edu/esf/rdbriggs/for345/cation.htm

[Mercedes Benzene]

By just skimming breifly through the article, it appears they are talking about ions (specifically cations) and their interaction with colloidal suspensions of clay-like materials.

First off, an ion is a charged particle. A cation is a positively charged ion.
The + and - they refer to denote the charges of the ion. They set it up very strangely in this article which is probably why you had a hard time comprehending what was going on.
For instance, they mention Al+++. Anywhere else, that would be very poor structuring. In chemistry you would write Al +3, or Al 3+ (with the "+3" as a superscript). This represents an Aluminum cation, that is, an Aluminum atom stripped of 3 electrons. Since electrons have a negative charge, taking away three would leave a positive 3 charge.

I hope this helps clear up things a bit. Let me know if you have any more questions, and I'll try to read the article more carefully.

[Michaelangelica]

Thankyou for your help.

Sorry i'm still lost
I don't have a starting point.

I need absolute basics