NAME: _________________________________________ Activity – Build an Atom We have discussed mixture, compounds, and elements. Now let’s examine the structure of the atom itself. You will use a simulation activity from the University of Colorado’s PhET Simulation Labs to examine the structure of the atom. 1. Search google for “phet build an atom”. Open the simulation “Build an Atom”. Click the play button. 2. Start with the Build Atom icon. 3. Make sure that all of the green <+> boxes on the right of the screen are open and show the <-> sign. Check all three boxes in the “Show” section at the bottom right. Your screen should look like this screen. 4. Drag a PROTON onto the x. What do you think the x represents? ________________________ a. What is the name of the element? ___________________ b. What is the charge? _________________ Mass number? ___________________ 5. Drag an ELECTRON to the center of the atom. Where does the electron go? ______________________ a. What is the name of the element? ___________________ b. What is the charge? _________________ Mass number? ___________________ 6. Drag a NEUTRON to the center of the atom. a. What is the name of the element? ___________________ b. What is the charge? _________________ Mass number? ___________________ 7. Drag a second neutron to the center of the atom. What happens to the element? _________________ 8. Drag two more PROTONS to the center of the atom. What is the name of the element? ____________ 9. Drag enough NEUTRONS to make the atom stable. How many neutrons did you add? ___________ 10. What is the mass number of this element? ________________ 11. Drag enough ELECTRONS to make this element neutral. How many electrons were required? _______ 12. Try making a stable, neutral nitrogen atom. a. How many protons are needed? ____________ neutrons? __________ electrons? __________ b. What is the mass number of the atom? _____________ c. There are actually two stable, neutral nitrogen atoms. Form the other stable, neutral nitrogen. What particle do you change to make the other version of the atom? ____________________ What is the mass number of this nitrogen atom? ____________ 13. Think!! Answer each statement with proton, neutron, or electron. Use the simulation for help. a. The name of the element is determined by the number of _____________________. b. The nucleus contains _______________ and _________________. c. The element is neutral (net charge of zero) when the number of _________________ and _________________ is equal. d. The mass number is determined by ________________ and __________________. e. An atom has a positive charge if the number of _______________ is greater than ______________. f. An atom has a negative charge if the number of _______________ is greater than ______________. 14. Click “Symbol” on the bottom of the screen. You should see this screen now. Make sure all three items in the “Show” box are selected. 15. Create a stable, neutral atom of beryllium. a. How many protons? _______ neutrons? _________ electrons? _______ b. Complete the box. Mass Number Atomic Number 16. Create a stable, neutral atom of fluorine. Complete the box. Mass Number Atomic Number 17. What two subatomic particles affect the mass of an atom? Why do you think the other particle does not contribute to the mass? 18. The atomic number is whole number found on the Periodic Table. What subatomic particle identifies the element? ________________________ ISOTOPES 20. Make two stable, neutral atoms of carbon. What is the difference between these two atoms? The two carbon atoms above are called ISOTOPES. Isotopes are represented with symbol notation and hyphen notation. 12 6𝐶 is the symbol notation for the carbon atom with an atomic number of 6 and a mass number of 12. The hyphen notation is carbon-12. 14 6𝐶 is the symbol notation for the carbon atom with an atomic number of 6 and a mass number of 14 The hyphen notation is carbon-14. Isotopes of Oxygen Make two stable, neutral atoms of oxygen. Complete the boxes. Write the symbol notation and hyphen notation for each isotope. Symbol Notation Hyphen Notation
