Post on 24-Dec-2015
Ionization Energy October 5*4*1, 2.009 * 103
Objective: SWBAT explain trends in ionization energy
across a periodic table Catalyst:
What is the octet rule? How many electrons will oxygen want to
gain or lose to become a full octet? What do you think would happen if
Magnesium lost 3 electrons?
Agenda
Catalyst Characteristics of Ionic Bonds Figure it out yourself: Ionization energy Practice, Practice, Practice Exit Question
Atoms
Some atoms are desperate to gain or lose electrons to fill out their octet!
But where do they get these electrons? The electron store?
NO! Outer space?
NO! Walmart?
NO! Other elements?
YESSSSSSSSSS!!!!!!
Bonding
Key Point #1: There are two main ways an atom gains or loses electrons:By completely transferring them to another element- Ionic Bond
By sharing electrons with another element- Covalent Bond
Ionic Bonds this week! Covalent bonds next week!
Ionic Bonds
When atoms come together through an ionic bond, it is called an ionic compound
They transfer electrons so everyone is happy!
Example of an Ionic Bond
Chlorine steals one of sodium’s electrons
Characteristics of Ionic Substances
Electrons are transferred
Bonds between metals and non-metals KNO2
More Characteristics of Ionic Substances
They make crystals!
High melting points
Good conductors of electricity when dissolved
Who can think of practical applications?
Why is tap water more conductive than distilled water?
Who can think of practical applications?
What is an electrolyte?
Do you think that Gatorade would conduct electricity?
Even more practical!
Humans’ skin is slightly ionic because of sweat that is produced…
Let’s see how one innovator took this fact to make a really cool invention…
Ionization Energy
Key Point #2: Ionization energy is the amount of energy it takes to remove the outermost electron from an atom.
REMEMBER THE OCTET RULE!
1st IONIZATION ENERGY
the energy required to remove the first electron from an atom
The 1st ionization energy DECREASES as you go down a family
The 1st ionization energy INCREASES across a period(more p+ have more pull on e-)
Multiple Ionization Energies
You are going to figure out a trend in multiple ionization energies.
This material is at a college level… but shucks, you guys are ready.
First things first, draw a Bohr model for four elements: Li, Be, B, C.
Electronegativity/Ionization Energy
IE1 – 1st Ionization energy
IE2 – 2nd Ionization energy
IE3 – 3rd Ion. en.Etc…
Ionization Energy
Can you figure out why there is such an increase in the red numbers?
Use your BOHR models!! (10 mins)
Li Be B C IE1 520 900 801
1086IE2 7,298 1757 2427 2353IE3 14,849 3660 4621IE4 25,026 6223IE5 37,830
Do you get it?
Why does it take more energy to remove Lithium’s 2nd electron than it takes to remove Carbon’s 4th electron?
Hint: Start with a Bohr model
Ionization Energies
Key Point #3:Breaking a full valence shell will cause a dramatic increase in ionization energy.
Guided Practice (GP)
Which has a higher 3rd ionization energySilicon or Magnesium?
Guided Practice (GP)
What has a higher 1st ionization energy?Sodium or Neon?
Guided Practice (GP)
What has a higher 2nd ionization energy?Boron or Sodium?
Guided Practice (GP)
What has a higher 4th ionization energy?Nitrogen or Fluorine?
Guided Practice (GP)
What has a higher 2nd ionization energy?Aluminum or Silicon?
Independent Practice (IP)
What you do not finish is HW!
GEE Test Practice:
Exit Question
Which element has a bigger 3rd ionization energy: Boron or Calcium?
Which element has the larger 1st ionization energy:Fluorine or Magnesium?