1. Unit 2 Review

2. For a specific element the number of ______________ is the same but the number of ________ and ___________ may vary. Multiple forms of the same element with varying numbers of neutrons are called ________________. The same element with extra or not enough electrons are called ________. Mass number = _______________ + _______________ What are the two ways to write an isotope of carbon with 7 neutrons?  1. _______________2. _______________ Protons NeutronsElectrons Isotopes # of Neutrons# of Protons Ions Carbon-13 13 6 C

3. Name the element which has: a. 1 proton _____________ b. 4 n0, 3 p+, 3 e-________ c. 30 n0, 26 e-, 26 p+_____________ d. 18 e-, 22 n0, 18 p+_____________ Hydrogen Iron Lithium Argon Barry (the Puma) MickeyMinnie

4. What are valence electrons? _________________________________ ___ How many valence electrons in the following atoms: a. Al ________b. P __________ c. Mg _________ The electrons in an atom’s outer most orbitals 35 2 R.I.P. Tina (the llama)

5. How do the electron configurations for the following elements end? a. K _________b. N __________ c. Kr _________ How are mass number and atomic mass different? 4s 1 2p 3 4p 6 Mass number is the mass of the protons and neutrons combined. Atomic mass is the average mass of the element’s isotopes.

6. Put the following people in order and then tell what they contributed to the understanding of the atom: - Rutherford, Dalton, Aristotle, Thomson, Bohr, Democritus, Chadwick Democritus: came up with the first idea of an atom Aristotle: disagreed with Democritus Dalton: published his atomic theory (5 principles) in early 1800’s * almost all still true today. Thomson: used Cathode Ray Tube Experiment to discover the first subatomic particle, the electron. Rutherford: used the Gold Foil Experiment to prove the existence of a small, dense, positive nucleus. Bohr: said electrons are in energy levels Chadwick: discovered the neutron (hard to find b/c neutral & in center.) Quantum Mechanics – current model of the atom.

7. Explain the gold-foil experiment and the cathode-ray tube experiment. Remember Gold Foil Essay.. Review notes Bob (the Manatee)

8. Why are atoms neutral? _____________________________ What is the charge of the nucleus of a Carbon atom? _____________________________ ParticleChargeMassLocation Electron Proton Neutron Approximately 0 Negative Space surrounding nucleus Positive1 Neutral1 Inside nucleus Equal numbers of negative electrons and positive protons positive

9. Complete the table: Include the mass number and atomic number in names or symbols as discussed in class. ElementSymbol#p#n#eMass #Atomic Number 49 2123 Aluminum-28 21 Al Be 13 Beryllium-954 23Vanadium-444423 28 Hydrogen-2 1513 111 H V 4

10. Complete the table: ElementElectron Configuration Orbital Notation Electron Dot Beryllium Sn (No Orbital Notation) S 1s 2 2s 2

11. Write the noble gas configuration for krypton. Also, draw the electron dot diagram. What shapes are s and p orbitals? S- SphereP- Dumbells

12. Explain, in your own words ground state for electrons. Explain, in your own words excited state for electrons. Ground state electrons in the lowest possible energy level are normal. Excited state electrons take on energy and jump energy levels. George (the Geko)

13. Why did the chemicals used in the “somewhere in the rainbow” lab give off colors when heated? The electrons absorbed the heat from the burner, causing them to jump up to the excited state. In order to return back to “ground state” the electrons must give off the extra energy – in the form of light. Paris HiltonThe Hulkvs.

14. Consider the electrons found in Sulfur. How many total orbitals are found in sulfur? _______ Of all these orbitals, how many are found on the 2nd energy level? _________ Of the orbitals found on the second energy level, how many different orbital shapes are there? _________ How many electrons could fit into the entire 2p sublevel? ______ How many electrons could fit into one 2p orbital? ___________ 9 4 2 6 2

15. Titanium has 5 naturally occurring isotopes. Calculate the average atomic mass. Sodium has two isotopes. Sodium-22 and Sodium-23. Which is more abundant? ________________ Mass (amu)% Abundance 45.9558.00 46.9527.30 47.94873.80 48.9485.50 49.9455.40 Sodium-23