PART I: ATOM SCREEN
Go to the website and choose the Build an Atom simulation: http://phet.colorado.edu/en/simulation/build-an-atom
- Click on the + sign for each of the boxes (element name, net charge and mass number) to view changes as you change the number of particles in the atom.
- What particle(s) are found in the center of the atom? _________________________________________________________
- Play until you discover which particle(s) determine(s) the name of the element you build. ___________________________
- What is the name of the following atoms?
- An atom with 3 protons and 4 neutrons: _____________
- An atom with 2 protons and 4 neutrons: _____________
- An atom with 4 protons and 4 neutrons: _____________
- Play with the simulation to discover which particles affect the charge of an atom or ion. _____________________________
- Fill in the blanks below to show your results:
- Neutral atoms have the same number of protons and electrons.
- Positive ions have ________________________________ protons than electrons.
- Negative ions have _______________________________ protons than electrons.
PART II: Symbol SCREEN
- Using the Symbol readout box, figure out which particles affect each component of the atomic symbol and how the value of the numbers is determined.
| Position in symbol box | Term to describe this information | Particle used to determine this | How the value is determined |
| a | Element symbol | protons | # of p will identify the element |
| b | p+ + e– | ||
| c | Atomic number | ||
| d | Protons, neutrons |
- Create a definition (using a complete sentence) for each of these items based on your labels from the atomic symbol above.
- Element Symbol
- Charge
- Atomic Number
- Mass Number
- In addition to atomic symbol, we can represent atoms by name and mass number. Complete the table below:
| Symbol | Name |
| Carbon-12 | |
- Each representation (Symbol and Name) in the table above provides information about the atom. Describe the similarities and differences between the Symbol and Name representations.
PART III: ISOTOPES
- Play with the simulation to determine:
- Which particles affect the stability of the atom? _____________________
- Which particles do not affect the stability of the atom? _______________
- What are the names of the stable forms of oxygen?
- Oxygen-16
- Oxygen-____
- Oxygen-____
- List all of the things that are the same about these atoms (ignore the electrons).
- List all of the things that are different about these atoms (ignore the electrons).
- The atoms in the previous question are isotopes of each other. Based on this information, list the requirements for two atoms to be isotopes of each other.
- Test your understanding of isotopes by examining the relationships between the pairs of atoms listed below:
| Atom 1 | Atom 2 | Relationship between atom 1 and atom 2 |
| Isotopes Same Atom, Not Isotopes of Each Other Different Element | ||
| Carbon-12 | Isotopes Same Atom, Not Isotopes of Each Other Different Element | |
| Argon-40 | Argon-41 | Isotopes Same Atom, Not Isotopes of Each Other Different Element |
| Boron-10 | Isotopes Same Atom, Not Isotopes of Each Other Different Element | |
| An atom with 13 protons and 13 neutrons | An atom with 14 protons and 13 neutrons | Isotopes Same Atom, Not Isotopes of Each Other Different Element |
