CHEMISTRY - ORBITALS MODULE #3

ORBITALS

Always in Motion

As you know, electrons are always moving. They spin very quickly around the nucleus of an atom. As the electrons zip around, they can move in any direction, as long as they stay in their shell. 

• Any direction you can imagine — upwards, downwards, or sidewards — electrons can do it. Electrons are constantly spinning in those atomic shells and those shells, or orbitals, are specific distances from the nucleus. If you are an electron in the first shell, you are always closer to the nucleus than the electrons in the second shell. 

Shell Basics

Let's cover some basics of atomic shells:
1.  The center of the atom is called the nucleus.
2.  Electrons are found in areas called shells. A shell is sometimes called an energy level.
3.  Shells are areas that surround the center of an atom. 
4.  Each of those shells has a name (K, L, M...). 

There are a couple of ways that atomic shells are described. The most general terms are the basic regions where you find electrons. Chemists use an "n" value, or the letters K, L, M, N, O, P, and Q. 

• The "K" shell is the one closest to the nucleus 
• "Q" is the farthest away
• For simple atoms, those "n" values usually match the row number on the periodic table and are also known as energy levels. 

The second description looks at how electrons act inside of the shells. There are certain patterns of movement. Chemists have described those patterns with the "l" value. 

• The "l" values tell you what suborbital an electron is found in. 

You will see the lowercase letters s, p, d, f, g, and h for the suborbitals. 
For example, 

• the electron in a hydrogen (H) atom would have the values n=1 and l=0. The single electron would be found in the "K" shell and the "s" suborbital. If you go on to learn about chemistry, you may see its description written as 1s1. 
• Helium (He) is still in the K shell (top row), but it has two electrons. The first electron would be 1s1 and the second would be 1s2. 
• What about lithium (Li) at atomic number three with three electrons? It would be described as 1s2 2s1. Why is that? 

Not all shells and suborbitals hold the same number of electrons. For the first eighteen elements, there are some easy rules. 

• The K shell only holds two electrons. 
• The L shell only holds eight electrons. 
• The M shell only holds eight electrons. 
• The N shell can actually hold up to 18 electrons as you move to higher atomic numbers. 
• The maximum number of electrons you will find in any shell is 32. 

Where Are the Electrons?
We can't really tell you exactly where an electron is at any moment in time. We can only approximate, or guess, where an electron is located. 
According to something called quantum theory, an electron can be found anywhere around the nucleus. Using advanced math, scientists are able to approximate the general location of electrons. These general areas are the shells and suborbitals. 

SCIENCE NEWS - ARTIFICIAL HEART #23

CHEMISTRY - ELEMENT OF THE DAY - NEON

ELEMENT of the DAY - NEON

Neon is an element that is made in many stars. It's quite common in the universe, yet is rare on earth. Since it usually exists as a monoatomic gas, neon can escape the atmosphere.  
Ten facts on Neon:

1. Neon is the fourth most abundant element in the universe.
2. Neon's occurrence in the Earth's atmosphere is 0.0018%.
3. The word 'Neon' comes from the Greek word neos, which means "new one".
4. It is the 2nd lightest inert gas after helium.
5. Neon is tasteless and odorless.
6. When excited electrically, neon gives off a bright red color, but the gas itself is colorless.
7. Neon is used to make advertising signs, high-voltage indicators, wavemeter tubes, television tubes and lightning arrestors. When liquefied, Neon is used as a cryogenic refrigerant.
8. While plastic and other materials have been used to contain Neon gas, the only material that can hold the gas, but let light escape is glass.
9. Neon is used in signs for a bright reddish orange light. All other colors are due to other noble gases or fluorescent lighting.
10. Neon is completely non-toxic and chemically inert, so it poses no threat to the environment.