Simulations & Videos for

# Lesson 4.3: The Periodic Table and Energy-Level Models

### Interactive Periodic Table Game

• Players read questions about energy levels and score points by picking the correct element as the answer.

### Image Energy Level Cross-Section

• Electrons are in regions around the nucleus that are different distances away from the nucleus.
• The electrons surround the nucleus in 3 dimensions but it is easier to show an energy level model in two dimensions like the model that looks like a target.

### Image Oxygen Atom

• This energy level model shows two electrons on the first energy level and six electrons on the second energy level.
• Since this atom has a total of eight electrons, it also has eight protons.
• The atom with eight protons in its nucleus (atomic number 8) is oxygen.

### Image Periodic Table of Energy Levels

• Each energy level holds a certain number of electrons before electrons go into the next level.
• 1st Period: Hydrogen and helium—Electrons go into the first energy level. After the first level has two electrons, the next electron goes into the second level.
• 2nd Period: Lithium to neon—Electrons go into the second level. After the second level has 8 electrons, the next electron goes into the third level.
• 3rd Period: Sodium to argon—Electrons go into the third energy level. After the third energy level has 8 electrons, the next electron goes into the fourth level.
• 4th Period: Potassium and Calcium—Electrons go into the fourth energy level.

### Video Sodium in Water

• A small piece of sodium metal is placed in water.
• The sodium reacts with the water and gets very hot, producing sodium hydroxide and hydrogen gas.

The demonstration shown in this video is very dangerous. Do not attempt to perform this demonstration.

Video used with permission from Chemical Education Exchange (ChemEd X)

### Video Potassium in Water

• A small piece of potassium metal is placed in water.
• The potassium reacts with the water and gets very hot, producing potassium hydroxide and hydrogen gas which ignites.
• The reaction of the potassium with water is similar to the reaction of sodium in water but hotter.

The demonstration shown in this video is very dangerous. Do not attempt to perform this demonstration.

Video used with permission from Chemical Education Exchange (ChemEd X)

### Video Calcium in Water

• Small pieces of calcium are placed in water.
• The calcium reacts with the water but does not get nearly as hot as either the sodium or potassium.
• Also, the calcium hydroxide produced forms a white solid in the solution which is different from the sodium or potassium.

The demonstration shown in this video is very dangerous. Do not attempt to perform this demonstration.

Video used with permission from Chemical Education Exchange (ChemEd X)

### Video Sodium in Acid

• Small pieces of Solid sodium metal are placed in two different concentrations of two different acids (hydrochloric acid and nitric acid).
• The sodium reacts most vigorously with the nitric acid, producing a flame and smoke.
• The sodium also reacts pretty strongly with the weaker concentration of hydrochloric acid.

The demonstration shown in this video is very dangerous. Do not attempt to perform this demonstration.

Video used with permission from Chemical Education Exchange (ChemEd X)

### Video Potassium in Acid

• Small pieces of solid calcium metal are placed in two different concentrations of two different acids (hydrochloric acid and nitric acid).
• The calcium reacts most vigorously with the hydrochloric acid, producing bubbles.
• The reaction between calcium and the acids does not get as hot as between sodium or potassium with the acids.

The demonstration shown in this video is very dangerous. Do not attempt to perform this demonstration.

Video used with permission from Chemical Education Exchange (ChemEd X)