IIIIII III. Periodic Trends (p ) Ch. 6 - The Periodic Table

A. Periodic Law zWhen elements are arranged in order of increasing atomic #, elements with similar properties appear at regular intervals.

B. Chemical Reactivity zFamilies ySimilar valence e - within a group result in similar chemical properties

zAtomic Radius ysize of atom © 1998 LOGAL zIonization Energy yEnergy required to remove an e - from a neutral atom © 1998 LOGAL zElectronegativity C. Other Properties

zAtomic Radius = ½ the distance between two identical bonded atoms 1. Atomic Radius

zAtomic Radius yIncreases to the LEFT and DOWN 1. 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 1. Atomic Radius

zFirst Ionization Energy = Energy required to remove one e - from a neutral atom. 2. Ionization Energy K Na Li Ar Ne He

zFirst Ionization Energy yIncreases UP and to the RIGHT 2. 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 dont want to lose e - 2. Ionization Energy

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

3. Electronegativity zThe measure of the ability of an atom in a chemical compound to attract electrons zGiven a value between 0 and 4, 4 being the highest

zWhy increase as you move right? yMore valence electrons, need less to fill outer shell zWhy increase as you move up? ySmaller electron cloud, more pull by + nucleus 3. Electronegativity

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

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

zWhich element has the higher electronegativity? yCl or F yBe or Ca Examples