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Unit 2 Review. # of Neutrons. # of Protons. 13. C. 6. Protons. Neutrons. Electrons. For a specific element the number of ______________ is the same but the number of ________ and ___________ may vary.
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# of Neutrons # of Protons 13 C 6 Protons Neutrons Electrons • 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. _______________ Isotopes Ions Carbon-13
Mickey Minnie Barry (the Puma) Hydrogen Lithium • 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+_____________ Iron Argon
R.I.P. Tina (the llama) The electrons in an atom’s outer most orbitals • What are valence electrons? ____________________________________ • How many valence electrons in the following atoms: a. Al ________ b. P __________ c. Mg _________ 3 5 2
2p3 4s1 • How do the electron configurations for the following elements end? a. K _________ b. N __________ c. Kr _________ How are mass number and atomic mass different? 4p6 Mass number is the mass of the protons and neutrons combined. Atomic mass is the average mass of the element’s isotopes.
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.
Bob (the Manatee) • Explain the gold-foil experiment and the cathode-ray tube experiment. Remember Gold Foil Essay.. Review notes
Equal numbers of negative electrons and positive protons • Why are atoms neutral?_____________________________ • What is the charge of the nucleus of a Carbon atom?_____________________________ positive Space surrounding nucleus Negative Approximately 0 Positive 1 Inside nucleus Neutral 1 Inside nucleus
Complete the table:Include the mass number and atomic number in names or symbols as discussed in class. Beryllium-9 Be 5 4 4 Vanadium-44 V 23 44 23 13 15 13 Al 28 13 Hydrogen-2 H 1 1 1
Complete the table: 1s2 2s2
Write the noble gas configuration for krypton. Also, draw the electron dot diagram. • What shapes are s and p orbitals? S- Sphere P- Dumbells
George (the Geko) • 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.
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 Hilton vs. The Hulk
9 • 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? ___________ 4 2 6 2
Titanium has 5 naturally occurring isotopes. Calculate the average atomic mass. Sodium has two isotopes. Sodium-22 and Sodium-23. Which is more abundant? ________________ Sodium-23