Slide 1 Periodic Trends Slide 2 New Vocabulary
Slide 1 Periodic Trends
Slide 2 New Vocabulary l. Electron Shielding The reduction of the attraction between a positively charged nucleus and its outermost electrons due to the cancellation of a portion of the positive charge by the innermost electrons
Slide 3 Atomic Radii Down a Group –Atomic radii generally increase as you move down a group –This trend is caused by the addition of an energy level from one row to the next
Slide 4 Atomic Radii Across a Period –Atomic radii generally decrease as you move across a period –This trend is caused by the increasing positive charge of the nucleus as protons are added
Slide 5 Atomic Radii Trend Visual
Slide 6 Review Vocabulary l. Ionization Energy The amount of energy needed to remove an outer electron from an atom in its ground state and in gas phase
Slide 7 Ionization Energy Down a Group –This trend is the opposite of atomic radii. –The closer or more tightly bound an electron is to its nucleus, the harder it will be to remove –As you move down a group, ionization energy decreases because the electrons are further from their nucleus
Slide 8 Ionization Energy Across a Period –This trend is also the opposite of atomic radii –As you move across a period, ionization energy increases because the electrons are closer to their nucleus.
Slide 9 Ionization Energy Trend Visual
Slide 10 Review Vocabulary l. Electronegativity The tendency of an atom to attract bonding electrons to itself
Slide 11 Review Vocabulary l. Electronegativity The tendency of an atom to attract bonding electrons to itself
Slide 12 Electronegativity Down a Group –This trend is the opposite of atomic radii. –Electronegativities generally decrease as you move down a group.
Slide 13 Electronegativity Across a Period –This trend is also the opposite of atomic radii. –Electronegativities generally increase as you move across a period. –This is because the Alkali Metals want to give away their single valence electron so that they will have the same electron configuration as a Noble Gas, S 2 P 6.
Slide 14 Electronegativity Across a Period Continued… –However, Halogens need just one electron to become like Noble Gases. –Therefore, the Halogens’ tendency to attract bonding electrons is very high.
Slide 15 Eletronegativity Trend Visual
Slide 20 Trend Summary
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