Periodic Table Trends
Trends of the Periodic Table: At the conclusion of our time together, you should be able to: 1. Give a trend across and down the Periodic Table for metallic characteristics, reactivity, atomic radius and ion radius, electron affinity, ionization energy, electronegativity, density, melting point and boiling point 2. Pick the element with the higher trend above from a list of several elements
Trends Page 16 A trend = how a physical or chemical property changes across a period and within a group. Atomic radius = size of the atom Electronegativity = ability of an atom to attract electrons. Ionization Energy = amount of energy required to remove 1 electron.
Atomic Radius Page 19 ½ the distance between the nuclei of two identical atoms that are bonded together. 1. Electron electron repulsion Makes radius larger 1. Very weak interactions
Atomic Radius con t 2. Proton electron attraction = Makes radius smaller Very Strong interactions
Proton electron attraction is a million times stronger than electron electron repulsion
Atomic Radius con t Down a group/family 3. Energy level, n, increases from top to bottom Radius gets larger by adding large amounts of electrons Think Bohr model (adding rings)
Atomic Radius Trends
Atomic Radius Trends Top to Bottom Left to Right Increases Decreases
Ionization Energy The energy required to remove one electron from a neutral atom. The closer to the nucleus, the harder to pull the electron. The farther away, more interference from other electrons, therefore, the easier it is to pull the electron.
Ionization Energy Trends
Ionization Energy Trends Top to Bottom Left to Right Decreases Increases
Electronegativity The ability of an atom to attract electrons. The most electronegative element is F Fluorine It is assigned the number 4 and all other values are based on that value.
Electronegativity Trends
Electronegativity Trends Top to Bottom Left to Right Decreases Increases
Periodic Trends Top to Bottom Left to Right Atomic Radii Ionization Energy Electronegativity
Page 20 Practice 1. Which has the bigger radius? 1. K or Cu Po or S 2. Which has the smaller electronegativity? 1. Al or Cl Sr or Ba 3. Which has the higher ionization energy? 1. B or F N or Sb
Practice Page 24 1. Which has the bigger radius? 1. Li or F Mg or Ba 2. Which has the smaller radius? 1. Al or P Rb or Fr 3. Which has the higher ionization energy? 1. Ca or Ni As or Bi 4. Which has the lower ionization energy? 1. Ga or Tl Y or Ag 5. Which has the higher electronegativity? 1. Au or Po Ge or Pb 6. Which has the lower electronegativity? 1. Sc or Fe C or Sn
Metallic Character 1. Low ionization energy 2. Low electronegativities 3. High luster shiny 4. Good conductor or electricity and heat 5. Malleable and ductile Most metallic element = Francium
Metallic Characteristic Trends Top to Bottom Left to Right Increases Decreases Conductivity Shininess Malleability Ductility
Non Metallic Character 1. High ionization energy 2. High electronegativities 3. Little or no metallic luster 4. Poor electrical and thermal conductors 5. Fewer solids Most nonmetallic element = Fluorine
Metalloid Character 1. Characteristics of both metals and nonmetals 2. Electronegativities between those of metals and nonmetals 3. Ionization energies between those of metals and nonmetals. 4. Boiling pts, Melting pts and Densities vary widely
Silicone 1. High luster 2. Brittle 3. Good conductor
Review of Ions Cations lose electrons, therefore they tend to be Positive Ions - Metals Anions gain electrons, therefore they tend to be Negative Ions - Nonmetals
Atomic vs Ionic Radii Less electron-electron repulsion = smaller radius More electronelectron repulsion = larger radius
Reactivity Trends metals.francium nonmetals Fluorine Top to Bottom Left to Right Increases with Metals Decreases with Nonmetals Decreases with Metals Increases with Nonmetals