Electron Configurations

Init: 10/07/09 by Daniel R. Barnes

Fraunhoffer Lines

http://www.youtube.com/watch?v=u9VMfdG873E&NR=1&feature=endscreen

Here. Play this while you’re making your 2p sublevels out of balloons.

Balloon P Sublevels

Pick a one partner.

One of the two of you, come up and get two balloons of the same color.

B low up your balloons to the same size as each other.

You now have one lobe each.

Tie the necks of your two balloons together as close as you can.

You now have a p orbital.

Get together with two other partner pairs of different colors and assemble a p-sublevel.

. . . describe the shape, number, position, and energy rank of the

various kinds of orbitals.

SWBAT . . .

You should already have learned by now that atoms are made mostly of . . .

However, that space isn’t quite empty.

There are ELECTRONS whizzing around the space surrounding an atom’s nucleus

However, electrons don’t orbit a nucleus exactly the same way that a planet orbits the sun.

The truth is far more bizarre than that.Electrons in an atom occupy energy states called “orbitals”, but there are some serious differences between an electron “orbital” and the orbit of a planet.

At any given time, a planet has a definite location in space, and it also has a definite speed and direction of motion.

An electron, on the other hand, has neither.

An electron merely has probabilities of being in certain locations and probabilities of moving with certain velocities.

This is a traffic ticket.

You can’t write a traffic ticket for an electron, because you can’t know its position and momentum simultaneously.

The more certain your measurement of one is, the less certain the reality of the other one becomes.

This is known as the “Heisenberg uncertainty principle”.

If you can’t know an electron’s position and motion at the same time, how can you possibly describe its “orbit”?

The moon orbits the earth.

Nice and simple, isn’t it?

Newton’s laws of motion allow us to predict the moon’s location and motion with pinpoint accuracy.

Therefore,we were able to aim our Apollo spacecraft perfectly so that they could “rendezvous” with the moon.

An electron’s “orbit” is nothing like the orbit of the moon.Electron motion is totally unpredictable. In fact, it’s indescribable.

Anything less than perfect accuracy would have meant dead astronauts.

Electron orbitals are nothing like planetary orbits.

1s

The lowest electron energy state in an atom is the “1s” orbital.

The 1s orbital is often represented as a spherical region of space.

The 1s orbital doesn’t truly have an outer boundary, but we draw one anyway.

In the 1s orbital, the electron is more likely to be found closer to the nucleus than farther from it. This is represented by the red color being most intense in the center and fading to black toward the outside.

The meaning of the yellow line is this: When an electron is in the 1s orbital, it is 90% likely to be inside the yellow line. The electron has a 10% probability to be outside of this “boundary”.

The essence of the 1s orbital is that the electron is more likely to be found closer to the nucleus than farther from it. This is represented by the red color being most intense in the center and fading to black toward the outside.

The meaning of the yellow line is this: When an electron is in the 1s orbital, it is 90% likely to be inside the yellow line. It has a 10% probability to be outside of this “boundary”.

The electron is very likely to be here, in the center, near the nucleus . . .

. . . not quite as likely to be here, at a medium distance from the nucleus . . .

. . . very unlikely to be here, far from the nucleus . . .

. . . and extremely unlikely, though still possible, to be this far away from that positive “nut” in the middle of the atom.

Until you attempt to “observe” or “measure” the position of the electron, it exists in all possible places at once, at none of them in particular..

It’s not until you measure its position that the electron makes up its mind and decides to be in a particular place.

Yes. Run while you can, little man.

At that point, as you become more certain about its location, you become less certain about the motion of the electron.

The very reality of the electron’s motion becomes indistinct as you distinguish the electron’s location.

Run from the quantum mechanics terror bird.

Click the picture above to watch a video on YouTube that discusses the wave-particle duality of electrons. It helps if you’ve taken a year of physics already, so that the interference pattern idea isn’t new to you.

Thank you, Tania Flores, for showing me that link. I grew a little .

1s 2s

The 1s orbital can only hold two electrons.

The third and fourth electrons in an atom exist in the “2s” orbital.

The 2s orbital is just like the 1s, only larger.

1s 2s

The 1s and the 2s orbitals don’t lie next to each other.They share a common center point.

Let’s superimpose them on top of each other, like they’re supposed to be.

1s 2s

2p

An atom with more than four electrons will have one or two electrons in the atom’s 2p orbitals.

“p” orbitals are made of two lobes each.

Some people think a p orbital looks like a peanut.

1s 2s

2px

1s 2s 2px

2py

1s 2s 2px 2py

1s 2s 2px 2py

2pz

1s 2s 2px 2py 2pz

1s2 2s2 2p6

This is what an atom with ten electrons looks like.

Its electron configuration would be written as you see above.

1s2 2s2 2p6

With the “boundaries” erased, it looks more like this . . .

It’s not exactly the neat little solar system Rutherford envisioned, is it?

Instead, it’s a hazy cloud of probability.

It’s a misty ghost with an indistinct existence.

The 2nd shell of an atom consists of two sublevels, the 2s and the 2p.

The 2p sublevel consists of three orbitals: 2px, 2py, and 2pz.

Each p orbital can hold two electrons, one “spinning up” and one “spinning down”.

An “s” sublevel is made of one orbital

A “p” sublevel is made of three orbitals

A “d” sublevel is made of five orbitals

An “f” sublevel is made of seven orbitals

An “s” sublevel is made of one orbital

A “d” sublevel is made of five orbitals

An “f” sublevel is made of seven orbitals

A “p” sublevel is made of three orbitals

s2 when full

p6 when full

d10 when full

f14 when full

CA Chemistry Standard 1g*:

Students know how to relate the position of an element in the periodic table to its quantum electron configuration and its reactivity with other elements in the table

WARNING: As with all things you are taught in school, the diagonal rule is an over-simplification of reality. It is a reasonable predictor of the “aufbau” order for electron orbital filling, but it is not to be trusted 100%.

1s 2s

2p

3s

3p

3d

4s

4p

4d

4f

5s

5p

5d

5f

5g

6s

6p

6d

6f

6g

6h

7s

7p

7d

7f

7g

7h

7i

First, we build the staircase . . .

1s 2s

2p

3s

3p

3d

4s

4p

4d

4f

5s

5p

5d

5f

5g

6s

6p

6d

6f

6g

6h

7s

7p

7d

7f

7g

7h

7i

Then, we draw the diagonal lines . . .

1s 2s

2p

3s

3p

3d

4s

4p

4d

4f

5s

5p

5d

5f

5g

6s

6p

6d

6f

6g

6h

7s

7p

7d

7f

7g

7h

7i

Finally, we follow the diagonal lines to get the aufbau sequence . . .

1s 2s 2p 3s 3p 4s 3d 4p 5s 4d 5p 6s 4f 5d 6p 7s 5f 6d 7p

9/16/2014Tuesday

GRADING PROGRESS:Chapter 4 Scratch = 20%

WARM-UP: What is the significance of the “staircase” on the periodic table I gave you?

SWBAT. . . Explain how the periodic table is structured.

HOMEWORK: ALL: 6.1 sxn assmt HONORS: Also 5.3 all

s pd

f

. . . make electron configurations

SWBAT . . . ACTUAL LESSON NEEDED!