IIIIII II. Periodic Trends Ch. 4 - The Periodic Table

zDirections: Copy the information on the slides into your notes. Copy the arrows that you see on the slides onto your periodic table that you colored. Label these arrows with the trend that is discussed on each of the slides.

A. Periodic Law zWhen elements are arranged by increasing atomic #, elements with similar properties appear at regular intervals. Reactivity Increases :

B. Atomic Radius Li Ar Ne K Na

zAtomic Radius – size of a neutral atom yDecreases UP and to the RIGHT B. Atomic Radius

zWhy larger going down? yHigher energy levels have larger orbitals yShielding - core e - block the attraction between the nucleus and the valence e - zWhy smaller to the right? yIncreased nuclear charge without additional shielding pulls e - in tighter B. Atomic Radius

zFirst Ionization Energy C. Ionization Energy K Na Li Ar Ne He

zFirst Ionization Energy- energy needed to remove the first electron. yIncreases UP and to the RIGHT C. Ionization Energy

zWhy opposite of atomic radius? yIn small atoms, e - are close to the nucleus where the attraction is stronger zWhy small jumps within each group? yStable e - configurations don’t want to lose electrons C. Ionization Energy

zSuccessive Ionization Energies yMg1st I.E.736 kJ 2nd I.E.1,445 kJ Core e-e- 3rd I.E.7,730 kJ yLarge jump in ionization energy occurs when a CORE electron is removed. C. Ionization Energy

yAl1st I.E.577 kJ 2nd I.E.1,815 kJ 3rd I.E.2,740 kJ Core e - 4th I.E.11,600 kJ zSuccessive Ionization Energies yLarge jump in I.E. occurs when a CORE e - is removed. C. Ionization Energy

D. Electron Affinity yEnergy change when an atom gains an electron. Electron affinity becomes more negative across a period.

D. Electron Affinity Fluorine: -328 KJ/mole F + e- F - Neon: 29 KJ/mole Ne + e- Ne - yNegative # means energy is released. This means fluorine wants to gain an electron. yPositive # means it takes energy. This means the element does not want to gain an electron.

E. Electronegativity zNumber assigned to an atom to represent the ability to attract electrons in a chemical bond (no units) yIncreases UP and to the RIGHT

E. Electronegativity zWhy smaller going down? yElements such as Cesium and Francium rarely form bonds (Example: Cs and Fr – 0.7 – lowest number) zWhy larger to the right? yThese elements need fewer e- to form ions and therefore, chemical bonds (Example: F – 4.0 – highest number)

zMelting/Boiling Point yHighest in the middle of a period. F. Melting/Boiling Point

yCations (+) xlose e - xGet smaller © 2002 Prentice-Hall, Inc. yAnions (–) xgain e - xGet larger G. Ionic Radius

zWhich atom has the larger radius? yBe orBa yCa orBr Examples:

zWhich atom has the higher 1st I.E.? yNorBi yBaorNe Examples

zWhich atom has the greatest electronegativity? yLi or F yAs or Cu

zWhich atom has the higher melting/boiling point? yLiorC yCrorKr Examples

zWhich particle has the larger radius? ySorS 2- yAlorAl 3+ Examples