Build a Molecule PhET

DIRECTIONS: In the "Single" section, use the atoms provided to build a molecule.

QUESTION: What do you notice in the trays at the bottom of the sim?

• Molecules

• Atoms

• Protons

• Neutrons

• Electrons

DIRECTIONS: Still in the "Single" section, drag and drop atoms from the trays into the blue area.

QUESTION: What happens (usually) when two atoms are brought next to each other in the blue space?

• They fly away from each other.

• They combine into a new, larger atom.

• They stick together.

• They disappear.

DIRECTIONS: In the "Single" section, observe how atoms interact to form molecules.

QUESTION: When you combine two hydrogen atoms and one oxygen atom from the first set of trays, what type of molecule is formed?

• Methane

• Water

• Carbon dioxide

• Oxygen

DIRECTIONS: Notice the "Your Molecules" section? It lists five different molecules you can build by toggling through the trays of atoms at the bottom of the screen. Once you have successfully built the five listed, reset and see if you can build at least one molecule not listed (there are at least three).

WRITE & DRAW: What was the name and molecular formula (letters with subscripts) of one of the additional molecules you were able to build? Write the name and formula in the box to the right and then draw the molecule.

DIRECTIONS: Go to the second set of trays in the "SINGLE" portion of the sim and you should see one tray with two hydrogen and another with two oxygen. Combine the two hydrogen into one molecule and the two oxygen together into a separate molecule. Next, click on the green "3D" button and select the "ball and stick" model in the new window that opens by clicking on the right button above the play/pause button. Finally, compare the structure of molecular hydrogen to molecular oxygen and answer the following:

QUESTION: Other than being made of different atoms, how are the two molecules different?

• In both molecules the atoms change.

• There is no difference.

• There is a single line in the oxygen molecule and a double line in the hydrogen molecule.

• There is a single line in the hydrogen molecule and a double line in the oxygen molecule.

DIRECTIONS: The lines you observed in the 3D models represent bonds between atoms, specifically covalent bonds (bonds where outer electrons, aka valence electrons, are shared between atoms). Go to the third tray, build the molecules shown in the image, click on the "3D" button, and observe the bonds in these molecules.

QUESTION: Based on what you observed with the previous question and this one, match the atoms with the number of bonds they can form according to the sim.

• 2

• 
• 1

• 
• 4

• 
• 3

• 

DIRECTIONS: In the "Single" section, experiment with different atom types and bonds.

QUESTION: Which of the following molecules can you create in the Single section?

• NaCl

• H₂O

• Cl₂

• O₃

DIRECTIONS: Go to the second tray of the "Single" section and you should notice a tray with two hydrogen and another with two oxygen. Use these to build a molecule of water (H₂O) and then click the blue button shown in the image to break the molecule apart. After breaking the water apart, add the last oxygen atom by connecting it to the one already there. Next, attach one of the loose hydrogen to each oxygen atom and observe what you have.

QUESTION: What will happen to the molecule’s structure and properties when you change it?

• The molecule will remain water, but it will become more reactive.

• The molecule will become hydrogen peroxide (H₂O₂), which has different properties.

• The molecule will remain the same, but its mass will increase significantly.

• The molecule will lose its ability to form hydrogen bonds, making it less stable.

DIRECTIONS: Carefully study the molecular formulas you encounter in the sim. The letters you notice represent different elements and are called atomic symbols. Atomic symbols are either one or two letters long, with the first letter always being capitalized and the second letter (if there is one) lowercase. Build some molecules

QUESTION: How does the molecular formula change when a molecule contains more than one atom of the same element?

• The molecule multiplies.

• The atomic symbol (letter/letters representing the element) are written multiple times as needed.

• A little number (subscript) is written to the left of the atomic symbol to indicate how many atoms there are.

• A little number (subscript) is written to the right of the atomic symbol to indicate how many atoms there are.

DIRECTIONS: Click the button at the bottom-center of the sim to launch the "Multiple" section of the sim. This portion of the sim works exactly like the first, but gives you more atoms to build with, especially in the last set of trays. Take some time to try to build all of the atoms listed under "Your Molecules." Once you've done this, try building any one of the following: a hydrogen with two different atoms connected to it, an oxygen with three atoms connected to it, a nitrogen with four atoms connected to it, and/or a carbon with five atoms connected to it.

QUESTION: What happens when you try any of the above scenarios?

• The atoms split into new atoms.

• The extra atom will not attach and is pushed away.

• A larger molecule was made.

• The sim restarted.