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This article explains the periodic trends of atomic radius, ionization energy, and electronegativity in terms of nuclear charge and shielding. It provides examples and a quick quiz to test your understanding.
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Periodic Trends Atomic Radiusdecreases Can you explain in terms of nuclear charge & shielding Atomic Radiusincreases
Periodic Trends Atomic Radiusdecreases Ionization Energy??? Electronegativity??? Electronegativity??? Ionization Energy??? Atomic Radiusincreases
Ionization Energy(IE): • energy requiredto remove an e– + Down a Group: decreases ↓ Across a Period: increases ↑ WHY?
First IE Trends + increasesacross a period • -due to greaternuclear charge • (more attraction) -due to more shielding (less attraction) decreasesdown a group
Example of Ionization Energy Trend • Arrange the following elements in order of increasing first ionization energy. Mg, Na, Si, Al
Electronegativity(EN) Trends increasesacross a period • -due to greater nuclear charge • (more attraction) • atom’s ability to attract bonded e–’s -due to more shielding (less attraction) decreasesdown a group
Example of Electronegativity Trend • Arrange the following elements in order of increasing electronegativity: B, Na, F, O
Overall Reactivity – Very Important! • The most reactive metals are the largest since they are the best electron givers. • The most reactive nonmetalsare the smallest ones since they are the best electron takers.
0 Overall Reactivity
Periodic Trends (Summary) Atomic Radiusdecreases Ionization Energyincreases Electronegativityincreases Can you explain all of this in terms of p’s and e’s? Electronegativitydecreases Ionization Energydecreases Atomic Radiusincreases nuclear charge shielding
Quick Quiz! • As you go across period 3 from Na to Ar, the energy needed to remove an electron from an atom ______________. A. decreases due to greater nuclear charge B. decreases due to less shielding C. increases due to greater nuclear charge D. increases due to less shielding
Quick Quiz. IE: 500 kJ 1500 kJ • Alkali metals have lower ionization energies than noble gases because _____________. A. alkali metals are smaller with more protons. B. noble gases are larger with more protons. • alkali metals are larger with lower nuclear charges. D. noble gases are smaller with fewer protons.
Quick Quiz. • Fluorine is the most electronegative element because it has ____________. A. more nuclear charge and more shielding B. less nuclear charge and more shielding C. more nuclear charge and less shielding D. less nuclear charge and less shielding
Periodic Trends (Summary) Atomic Radiusdecreases Ionization Energyincreases Electronegativityincreases Can you explain all of this in terms of p’s and e’s? Electronegativitydecreases Ionization Energydecreases Atomic Radiusincreases nuclear charge shielding