Tyleralp1's Chemistry Question Thread

[Tyleralp1]

Hey everyone, I'd appreciate any help on the following:

Difference between molecules and compounds
Difference between mass and atomic mass
Difference between orbitals, shells and subshells

[nerdmmb]

Hey everyone, I'd appreciate any help on the following:

Difference between molecules and compounds
Difference between mass and atomic mass
Difference between orbitals, shells and subshells

Molecules are two or more atoms (of the same element or different elements) chemically bonded together.
Compounds are molecules whose atoms belong to different elements.

Analogy:
Think of a shell as a house, think of the rooms as subshells and think of the people inside the rooms as orbitals.

A shell is an energy level within an atom. Shells are further broken down into subshells. There are many different types of subshells but the ones that are important are the s, p, d and f subshells.
The s subshell can hold 1 orbital, the p subshell can hold 3 orbitals, the d subshell can hold 5 orbitals, the  f subshell can hold 7 orbitals and vice versa.

Orbitals are simply compartments within subshells that store electrons.
Each orbital no matter what subshell, can hold a maximum of 2 electrons.
The first shell in an atom has the s subshell, the second shell has the s and then the p subshell, the third shell has the s then the p and then the f subshell and so on.

So basically all together, the s subshell can hold 2 electrons, the p subshell can hold 6 electrons, the f subshell can hold 10 electrons and the f subshell can hold 14 electrons. For example, the fourth shell in an atom obviously has the s, p, d and f subshell so the total number of electrons would be (1x2 + 3x2 + 5x2 + 7x2) = 32


I hope you can see the pattern here
There is also something called the subshell configuration which is a detailed version of the electron configuration but it just shows the number of electrons occupied by each subshell.


And not too sure about your second question but hope this helped!

[lzxnl]

Hey everyone, I'd appreciate any help on the following:

Difference between molecules and compounds
Difference between mass and atomic mass
Difference between orbitals, shells and subshells

Molecules, by convention, refer to discrete covalent molecules. Sodium chloride, for instance, does not exist as a molecule because it consists of ionic attractions between ions. Similarly, I don't think you'd call diamond as consisting of molecules. Compounds can refer to both molecular and ionic compounds. It's a broader class of chemicals.

What "mass" are you asking for? The mass of what? Relative atomic mass is the average mass of a particular atom. The reason why I say average is because it factors in the varying abundances of different isotopes. For instance, carbon's relative atomic mass of around 12.011 amu is different from carbon 12's exact (rest) mass of 12.000 amu because there are more massive isotopes of carbon, such as carbon 13 and carbon 14.

Shells and subshells can be thought of as large energy levels. Different shells have large energy differences, while individual subshells, like 2p and 2s, have smaller energy differences (except for that of hydrogen in which the subshell number doesn't affect the energy). The orbitals form subshells and are a region in which an electron has a 90% probability of being found. In quantum mechanics, orbitals are therefore just a probability density; electrons are more likely to be found in some places than others.
Normally, the different 3d orbitals have the same energy. There are some cases where this degeneracy is broken (such as in transition metals, but you don't need to worry about that). Each orbital is also capable of holding two electrons, as you already know.

In chemical reactions, orbitals interact to form chemical bonds. After all, that is where the electrons are. You don't need to know the specifics of orbital interaction though; you don't even need to know about orbitals for 3/4 chemistry. In fact, your third question isn't necessary for 3/4 either xP there's not that much theory in VCE chemistry as a lot of it is calculation