today is tuesday, september 15 th, 2015 pre-class: we will be starting with a concept map today,...

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Today is Tuesday, September 15 th , 2015 Pre-Class: We will be starting with a concept map today, followed by some information…and stuff… In This Lesson: Compounds, Electron Configuration (Lesson 3 of 9)

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Today is Tuesday,September 15th, 2015

Pre-Class:We will be starting with a concept map today, followed by some information…

and stuff…

In This Lesson:Compounds,

Electron Configuration(Lesson 3 of 9)

Today’s Agenda

• Concept map review.• Review of Guiding Questions.• Understand compounds.• Diagram electron configuration.• Learn bonds (soon).• Properties of Water (not as soon but still soon).

• Where is this in my book?– Academic: p. 35 and following…– Honors: p. 19 and following…

By the end of this lesson…

• You should be able to identify the basic structure of compounds.

• You should be able to properly place electrons around a nucleus with respect to energy levels.

Atom Concept Map Review

• Everyone should copy this down.– Makes for a great study guide…

• Volunteer(s)?

Guiding Questions

• Recently we looked at a series of what I called Guiding Questions.

• For review, here they are…

Guiding Questions(Write these down)

1. Is it okay to use the number of electrons as a measure of atomic number?

2. What happens if you remove or add a proton?3. What happens if you remove or add a neutron?4. What happens if you remove or add an electron?

Guiding Question 1

• Is it okay to use the number of electrons as a measure of atomic number?– No – in ions, the number of electrons does not

equal the atomic number.

Guiding Question 2

• What happens if you remove or add a proton?– Adding a proton changes the element!– This does not often happen in nature.– Let’s say you have Hydrogen. It’s got one proton. – We add a proton, so now it has two. Which

element has two protons?• Helium.

Guiding Question 3

• What happens if you remove or add a neutron?– You’ll create a new isotope.– Same element, same number of protons, new

number of neutrons, new atomic mass.

Guiding Question 4

• What happens if you remove or add an electron?– You’ll create an ion.– An ion is an electrically-charged atom.

Compounds

• As we learned recently (briefly), a compound is a chemical combination of two or more elements.– Examples of compounds:

• Water• Salt• Hydrochloric Acid (stomach acid)• Sulfuric Acid (“ouch” acid)• Carbon Dioxide• Carbonic Acid (similar to soda water)• Glucose (simple sugar)

Compounds

• In compounds, elements are held together by some kind of bond (more on bonds later today/tomorrow).– The smallest unit of an element is called an atom.– The smallest unit of a compound is called a molecule.**

• Compounds generally form through a chemical reaction, in which bonds are broken, rearranged, or formed.– Speaking of chemical reactions…– Video! Chemical Reactions – NOVA

Compounds vs. Elements

• Remember that writing an element is as easy as its abbreviation:– H, Cu, Hg, Li, He, O, C

• Writing a compound means writing all the elements in the compound, as well as how much are in there.– Examples next slide…

Compounds

• Compound Examples:– Water (H2O – 2 Hydrogen atoms and 1 Oxygen atom)– Salt (NaCl – 1 Sodium atom and 1 Chlorine atom)– Hydrochloric Acid (HCl – 1 Hydrogen and 1 Chlorine)– Sulfuric Acid (H2SO4 – 2 Hydrogen, 1 Sulfur, 4 Oxygen)

– Carbon Dioxide (CO2)

– Carbonic Acid (H2CO3)

– Glucose (C6H12O6)

Making Compounds

• As we said, compounds form from bonds.• To understand bonds, we need to understand

electron configuration.• Electron configuration refers to how the

electrons are organized in that cloud around the nucleus.

• Note (but not in your notebooks): What you’re about to hear is the simplified biology version. The chemistry version is MUCH more complicated/realistic.

Electron Configuration

• In any given atom’s electron cloud, we say there are energy levels or energy shells.

• By this, we mean that there are levels closer to the nucleus (lower energy levels) and levels further from the nucleus (higher energy levels).

• Picture on next slide…

Electron Configuration

http://www.physics.uiowa.edu/adventure/fall_2005/oct_15-05/energy_levels.gif

• The electrons in the outermost energy shell (however far out that may be) are called valence electrons.

• Valence electrons are the only ones that matter in bonding.

Electron Configuration

• “Filling” electron shells with electrons is easy.• You already know how to calculate the total

number of electrons in an atom or ion.• Fill the shells in a 2-8-8 pattern.– We won’t often be going higher than atomic

number 18 in this class.– Example on next slide.

Electron Configuration

• Let’s fill the shells of Aluminum, atomic number 13. This means there are how many electrons in an uncharged atom?– 13

• Remember the 2-8-8 pattern!• First shell: 2• Second shell: 8• Third shell: 3– 3 valence electrons, and the third shell is the valence

shell in this case.

From ChemicalElements.com

• Take a look at the aluminum atomic diagram to the right. What do you see?

• Another place to look:– David’s Whizzy Periodic Table• http://

www.colorado.edu/physics/2000/applets/a2.html• Linked on my website.

Electron Configuration

• Now it’s your turn.• Fill the shells of the following atoms in your notebooks, and

write how many valence electrons there are:– Carbon– Oxygen– Beryllium– Fluorine– Hydrogen– Helium– Neon– Magnesium– Sulfur

Electron Configuration

• Carbon (Atomic Number 6)– 2, 4 [4 valence electrons]

• Oxygen (Atomic Number 8)– 2, 6 [6 valence electrons]

• Beryllium (Atomic Number 4)– 2, 2 [2 valence electrons]

• Fluorine (Atomic Number 9)– 2, 7 [7 valence electrons]

Electron Configuration

• Hydrogen (Atomic Number 1)– 1 [1 valence electron]

• Helium (Atomic Number 2)– 2 [2 valence electrons]– Notice something about helium?

• Neon (Atomic Number 10)– 2, 8 [8 valence electrons]– Notice something about neon and helium?

Electron Configuration

• Magnesium (Atomic Number 12)– 2, 8, 2 [2 valence electrons]– Notice something about magnesium and

beryllium?• Sulfur (Atomic Number 16)– 2, 8, 6 [6 valence electrons]– Notice something about sulfur and oxygen?

Electron Configuration

• What’s going on with helium and neon?– How many valence electrons?

• 2 and 8

– How many more can you fit in their outermost energy shells?• None! The valence shells are at capacity!

• These, and all the elements in the same column below them, are called the noble gases.

• Because their valence shells are full, they don’t really react with anything.– They also were among the last elements to be discovered.

• Think of a snooty “noble” person. That’s how they were named!

Electron Configuration

• And what about their location on the periodic table?

Electron Configuration

• Now what about Beryllium and Magnesium?– How many valence electrons for each?– 2!

• And how about Oxygen and Sulfur?– 6 each!

• And what about all of their locations on the table?

Electron Configuration

• And what about their location on the periodic table?

Electron Configuration

• There is a pattern to the periodic table for valence electrons!

• Work by columns (which are called groups).• Start from the left and ignore the lower

middle part.– The first column or group has 1 valence electron,

the second has 2, et cetera.• Rows, by the way, are called periods.– Hence, periodic table of elements.

Electron Configuration1

2 3 4 5 6 728

Dmitri Mendeleev

• Looks like he was on to something when he arranged the table…

http://reich-chemistry.wikispaces.com/file/view/Dmitri_Mendeleev.jpg/98117907/Dmitri_Mendeleev.jpg

One last thing…

• If you’re dealing with an ion (say for example Al3+), make sure you get the new number of electrons.

• Al3+ has 13 protons and 10 electrons, so the arrangement is:– First shell: 2– Second shell: 8

• Total: 10 electrons

A “Trailer” for Next Class

• TED: George Zaidan and Charles Morton – How Atoms Bond

And so now we dothe Review and WhipAround…

• First, play Electron Configuration Matching Game on Quia.

• Then, try Atomic Structure and Electron Configuration Battleship.

• Then, try Atomic Structure Review Quiz.– Write both your names in the survey question.

• Find some space in your notebook and write down two things you learned about:– Electron Configuration– Compounds