Thursday, February 14, 2013

Chapter 2: Composition and Chemistry of Life - Part 2

-_- Science is such a bore sometimes, isn't it? Don't we just hate it sometimes? Don't we just want to throw this journal of ours' into the nearest digital trash can? Yes, yes we do; but come on, we can show those lovely textbooks that Science is made up of more than just long, dull paragraphs!

We left part 1 (a long time ago I might add) with a definition of what made up an atom... So, want to review? Um, ah, mm, meh, uh... No, we don't. Normally that would be terrible, but since this is a journal where we are putting down our lessons, we can just read the previous post so there's no need to review *pumps fists*. We're not done though, so keep reading because we're moving onto the more detailed part of Chemistry Life.

The Categories

I wonder if scientists have OCD (Over Compulsive Disorder). I mean, is that why they feel inclined to list, label, categorize, and otherwise organize every single little detail in the world of Science? We have to admit though, in the long run it does make it easier to remember everything when it's categorized just so. With that in mind I suppose its no surprise to us when we read these next few ways of organizing what-is-what and who-is-who regarding atoms.

Atomic Properties

Now we're going to go over how atoms behave when they're with other atoms, and it has a lot to do with their Electron Shells so it's a good thing we went over those very things in part 1. The properties of an atom means how one atom behaves when it meets another while strolling through the supermarket. What? That's not the case? Well, we're not that far off anyways. The true definition: the properties of an atom (or how an atom behaves when exposed to other atoms) are determined mostly by the number of electrons that atom has. According to my lovely textbook, it has been proven that atoms possessing Electron Shells with less then the maximum number of electrons it can hold (or simply put: unfilled Electron Shells) are more likely to combine (react) to other atoms with unfilled Electron Shells. Likewise, atoms with filled Electron Shells (have close to the maximum number of electrons) are less likely to react with other atoms with filled Electron Shells.

Remember that the maximum number of electrons in the first shell is 8. So obviously the atom on the right hand side has a full shell (which, FYI, is Neon. No, not Neon like "Neon Green". Neon like the element. There's an element called Neon? Yes, yes there is). Because the element of Neon has a full electron shell, it's harder for it to react to other elements because there's no place in the first shell for another electron from another atom to attach to. In the atom on the left hand side (Carbon), there's lots of room for more atoms to join in. Only four electrons are in the first shell of the Carbon atom, so another four electrons can join in.

Atomic properties depend a lot on the formation of an atom's Electron Shell. What do we mean by this? Well, say we have an atom whose electron shell is unfilled, but most of it's electrons are on the outer levels of the shell. Those electrons act as a wall towards other atoms, preventing them from reacting with each other. It's sort of like when your friend crosses his arms when you try to hug him, so your just sort of left in an awkward position... *silence*... Was that the best analogy we could come up with? -_- Never mind. The point is atoms find it difficult to react with one another if they have a lot of electrons in their outer levels.

Isotopes

What kind of a wacky name is "Isotope"? The scientist that made this one up must have been having a good morning; or it could just be that the Greek roots isos and topos mean equal and place, which would make a lot more sense. As we all know by now, an element (another word for atom) is defined by the number of protons and elections it has (as seen in the previous part of Ch 2). There is only one atom which contains 6 protons and 6 electrons, and that is Carbon. As my lovely textbook states "All elements (atoms) are defined by the number of protons and electrons the atom contains."

However there are some atoms that can contain different numbers of neutrons and still be the same element. Like we were going over before, some elements have different forms that can change in the number of neutrons they contain. These special atoms are called Isotopes. "Why is this important?" We ask, "After all it's the electrons and protons that define an atom." Well, the neutrons have a role to play too, not just the dashing little electrons and bulky protons; this "third wheel" is important!

Let's continue using carbon as an example, shall we? According to my lovely textbook, there are three isotopes of Carbon: Carbon 12, Carbon 13, and Carbon 14. Each one still contains 6 protons and 6 electrons, but Carbon 12 has 6 neutrons to go along with the 6 protons in the nucleus, so it's Atomic mass is more or less 12 (this is the isotope we put up as an example, and we didn't even know it!). Carbon 13, on the other hand, has 7 neutrons sitting next to its 6 protons, so its Atomic mass is roughly 13 . On our imaginary third hand, Carbon 14 had 8 neutrons living besides 6 protons, raising the Atomic mass of this isotope to about 14. Due to the fact that all three isotopes still have 6 protons and 6 electrons, they all behave the same way, but their build (the way they're made) is not the same because of those different neutrons (the third wheel's not such a third wheel now, hehe).






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