[justin_lake888]

What type of orbital characterized the quantum numbers? is it all orbitals of an atom or all orbitals of a molecule or each different orbital? I am a little confused about this.

[kyle1990]

i don't quite understand the question, but this may help: there are 4 quantum numbers:

n= principle quantum number
this represents the size of an orbital. The larger the value of N, the larger the orbital. for example, the 4s orbital is larger than the 3s orbital. 4 and 3 = principle quantum number

l= angular quantum number (that's L not I)
l represents the shape of the orbital. There are 4 shapes orbitals can take form of:
s, p , d, f

s orbitals are spherical, like a "shell". These orbitals exist when l=0.
p orbitals are dumbell-shaped, existing when l=1
d orbitals are somewhat complex, and exist when l=2
f orbitals are highly complex, when l=3

m=magnetic quantum number
describes the orientation of the orbital in space. for instance, there are 3p orbitals, each are orthogonal (all orbitals are 90 degrees rotated) from each other. m can have values ranging from -l,l, where l is the angular quantum number.

s=spin quantum number
this just describes the spin of the electron as either +1/2 or -1/2

I hope this gives you some insight

[justin_lake888]

hey thanks for the info...

yeah the question I am working on is worderd strangely...its like a multiple choice question...
its saying that type of orbital are the quan. numbers characterized?

1. all orbitals of an atom
2. each different orbital
3. all orbitals of a molecule
4. all of the above

i know 4. is wrong... I think the answer is 2. what do you think?

[kyle1990]

the orbitals of an atom. more specifically, an orbital is described by three of the four quantum numbers (n, l, and m). the spin quantum number is not that unique to a particular orbital, since all electrons in any orbital have a +1/2 spin or a -1/2 spin.

maybe this explanation will clear things up for you. The electrons moving about a nucleus ( note we are talking about the nucleus, so it must be a single atom, not a molecule), are described in quantum mechanics by wave functions (literally as in mathematics-wave fuctions). The wave functions for one electron is called an orbital wave function, and the elctron is said to occupy an orbital (rather than an orbit). The use of the word orbital and not orbit indicates that the motion of the electron according to quantum mechanics is not the same as the planetary motion surmised by Bohr.
Pauling, Linus: General Chemistry, pg122: Dover Publications
So in short, an orbital is an area in space wheere the electron is most likey to be found. Look up electron density maps online for a better visual

[justin_lake888]

ok... I got it now. That makes sense. choice 2 each different orbital doesn't make sense.

also I have a question regarding properities of an electron... they only have wave properities right? or do they have both wave and particle properities?

[kyle1990]

it has both but it depends on the experiment. For instance, light waves interfere to produce bright "spots" and dark "spots". Interference is a property of waves. However, if you consider the photoelectric effect, a photon (electron essentially) is ejected from the surface of a metal at a certain frequency of light. Notice how it is ejected and treated as a particle. So it is in fact both. It just depends on the experiment as to which one it will behave as.

[justin_lake888]

i am working on this problem - calculate the momentum if the energy of photon is 25 x 105 erg?

This is my solution:
I would get....

p=E/c
(25*10^5 erg)/(3*10^8 m/s)= 8.3*10^-3 erg*m/s

is that correct? ...also am i wrong about the units... are the units of photons, joules?