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Periodic Trends. http://www.youtube.com/watch?v=QSZ-3wScePM. 6.1 Organizing the Elements The Periodic Table. 6.3 Periodic Trends. Properties that change in a predictable pattern as you move through the periodic table. XOOXOOXO. 6.3 Periodic Trends. Electron Shielding
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Periodic Trends http://www.youtube.com/watch?v=QSZ-3wScePM
6.3 Periodic Trends • Properties that change in a predictable pattern as you move through the periodic table. • XOOXOOXO
6.3 Periodic Trends • Electron Shielding • The ability of the core electrons to shield the outer electrons from the nucleus • Atomic Radius • The size of the atom • Ionization energy • The energy needed to remove an electron • Electronegativity • The tendency of an atom to attract an electron while in a bond
6.3 Periodic Trends Atomic Radius • The distance from the center of the nucleus to the outermost electron • Increases going down a group • Electron Shielding increases • Outer electrons are able to move farther from the nucleus • Decreases going across a period • Electrons shielding remains constant • The nucleus pulls the electrons closer.
6.3 Periodic Trends Ionic Size • Size of an ion • Cations (positive ions) are smaller than the atom they came from • Anion (negative ions) are larger than the atom they came from • Increases down a group • Positive ions decrease and then negative ions decrease across a period
6.3 Periodic Trends Ionization Energy • The energy needed to remove an electron from an atom to give a charge of positive one • Increases across a period • Atomic size decreases, outer electrons are harder to pull off • Decreases down a group • Atomic size increases, outer electrons are easier to pull off
6.3 Periodic Trends Electronegativity • The ability of an atom to attract an electron while it is in a bond. • Increases across a period • Atomic size decreases, easier for the nucleus to attract other electrons • Decreases down a group • Atomic size increases, harder for the nucleus to attract other electrons • Noble gases do not have electronegativities because they are typically not involved in bonds
6.3 Periodic Trends 11 • How many electrons are in a Sodium Atom? • 3 • How many energy levels are there in a Na atom? • 2,8,18,32 • How many electrons go in levels 1,2,3 and 4? • In our Na atom how many electrons will go in each level? • 2,8,1