11 Chem, week 3 - Don't be so Negative!
Hey y'all, it's Liam again. Let's go straight into it!
The only new concept I learned about this was electronegativity (although it was a challenge unto itself). Electronegativity is the reason that molecules such as BrCl and pure water molecules are polar. Every atom has a relative value of how much they want new electrons. For instance an alkali metal would normally have an electronegativity value that rests slightly lower than one as the alkalis would rather get rid of their electrons than gain new ones. On the other hand, the halogens have very high electronegativity values, averaging around 2.5. Now, keep in mind that these values are relative to each other, so the values are dimensionless and thus have no units (Linus Pauling basically created the concept of electronegativity and came up with the most common way of calculating electronegativity values.)
While some bonds can be polar (we call these polar covalent bonds) there are others that are non-polar. (unsurprisingly, non-polar covalent bonds) One of these bonds has an electrical charge, while the other does not. Can you guess which type of bond goes where?... Please tell me I have no idea. I'm kidding! Of course, the polar covalent bonds have the electrical charge. Now, this happens because when two atoms bond, one atom usually wants the bonding pair of electrons more than the other atom and when you get THIS happening (the electrons going closer to one atom than the other (because of electronegativity!)) one atom becomes slightly negative, and the other becomes slightly positive. However, when diatomic bonds form, the atoms in the molecule have the exact same electronegativity value, and when this happens you get non-polar covalent bonds!
One concept to get down pat before looking at other ways of creating different kinds of bonds is the concept of dipoles. This term can actually refer to a) the polarity of an individual bond within a molecule, b) the net charge of all polar covalent bonds within a polar molecule, or c) a polar molecule itself. For instance, the diatomic molecule of N2 has no dipoles (a) within it, and is not a dipole itself (c). This is because N2 has one non-polar covalent bond, and is not polar.
Another way to get a non-polar covalent bond is to have one atom surrounded by two or more of the same atom. Even if the surrounding atom and the middle atom's electronegativity values are different, each surrounding atom will pull on their bonding pairs of electrons (dipole concept a, each bond is itself a dipole because each bond is a polar covalent bond) the same amount as the other surrounding atoms, meaning that the electronegativity of the dipole (dipole concept c) as a whole will be zero.
Oh yeah, and then I studied a bunch for the unit 1 test.
(Here's a handy link for a simpler explanation of electronegativity and bonding)
Update on the vibrating mouse: I've deciphered several of the morse-code sounds coming from my mouse, although some have yet to be determined. Here's the full message (after these sounds the message seems to repeat): S____M__A__FL__N__NT_TH__UN. What does this mean??
Thank you for reading, hopefully you found some joy with this nice peak into my chemistrical life (Is that a word? I don't think it's a word) and I hope to keep providing said entertainment until we finish our little journey together! As a side note, I'm quite new to blogging so please don't be perturbed by my lack of anything stylish. I'll try my best to learn how to do this right, even as I continue to be unable to see my reflection. (Is that a problem? I feel like that's a problem)
The only new concept I learned about this was electronegativity (although it was a challenge unto itself). Electronegativity is the reason that molecules such as BrCl and pure water molecules are polar. Every atom has a relative value of how much they want new electrons. For instance an alkali metal would normally have an electronegativity value that rests slightly lower than one as the alkalis would rather get rid of their electrons than gain new ones. On the other hand, the halogens have very high electronegativity values, averaging around 2.5. Now, keep in mind that these values are relative to each other, so the values are dimensionless and thus have no units (Linus Pauling basically created the concept of electronegativity and came up with the most common way of calculating electronegativity values.)
 |
| Dr. Linus Pauling (hey look I figured out how to add pictures!) |
While some bonds can be polar (we call these polar covalent bonds) there are others that are non-polar. (unsurprisingly, non-polar covalent bonds) One of these bonds has an electrical charge, while the other does not. Can you guess which type of bond goes where?... Please tell me I have no idea. I'm kidding! Of course, the polar covalent bonds have the electrical charge. Now, this happens because when two atoms bond, one atom usually wants the bonding pair of electrons more than the other atom and when you get THIS happening (the electrons going closer to one atom than the other (because of electronegativity!)) one atom becomes slightly negative, and the other becomes slightly positive. However, when diatomic bonds form, the atoms in the molecule have the exact same electronegativity value, and when this happens you get non-polar covalent bonds!
One concept to get down pat before looking at other ways of creating different kinds of bonds is the concept of dipoles. This term can actually refer to a) the polarity of an individual bond within a molecule, b) the net charge of all polar covalent bonds within a polar molecule, or c) a polar molecule itself. For instance, the diatomic molecule of N2 has no dipoles (a) within it, and is not a dipole itself (c). This is because N2 has one non-polar covalent bond, and is not polar.
Another way to get a non-polar covalent bond is to have one atom surrounded by two or more of the same atom. Even if the surrounding atom and the middle atom's electronegativity values are different, each surrounding atom will pull on their bonding pairs of electrons (dipole concept a, each bond is itself a dipole because each bond is a polar covalent bond) the same amount as the other surrounding atoms, meaning that the electronegativity of the dipole (dipole concept c) as a whole will be zero.
Oh yeah, and then I studied a bunch for the unit 1 test.
(Here's a handy link for a simpler explanation of electronegativity and bonding)
 |
| Real picture of me being excited for the test (actually this is Tim Cook being "incredibly excited" about Apple's earnings) |
Update on the vibrating mouse: I've deciphered several of the morse-code sounds coming from my mouse, although some have yet to be determined. Here's the full message (after these sounds the message seems to repeat): S____M__A__FL__N__NT_TH__UN. What does this mean??
Thank you for reading, hopefully you found some joy with this nice peak into my chemistrical life (Is that a word? I don't think it's a word) and I hope to keep providing said entertainment until we finish our little journey together! As a side note, I'm quite new to blogging so please don't be perturbed by my lack of anything stylish. I'll try my best to learn how to do this right, even as I continue to be unable to see my reflection. (Is that a problem? I feel like that's a problem)
Comments
Post a Comment