Electron Affinity
The energy change occurring when an anion of the element in the gaseous phase loses an electron
Across a Period: Electron Affinity
Increases. Why? Greater Positive Nuclear Charge
Down a Group: Electron Affinity
Decreases. Why? 1) Increased number of energy levels 2) Increased electron repulsion
Ionization Energy
The energy required to remove an electron from an atom
Across a Period: Ionization Energy
Increases. Why? Greater Positive Nuclear Charge
Down a Group: Ionization Energy
Decreases. Why? 1) Increased number of energy levels 2) Increased electron repulsion
Moseley
Revised periodic table and arranged elements according to Atomic Number
Mendelev
Proposed 1st periodic table where elements were arranged according to Atomic Mass
Chemical Reactivity - Families
Similar valence electrons in a group result in similar chemical properties
Electronegativity
The tendency for an atom to attract electrons to itself when it is chemically combined with another element
Across a Period: Electronegativity
Increases. Why? Greater Positive Nuclear Charge
Down a Group: Electronegativity
Decreases. Why? 1) Increased number of energy levels 2) Increased electron repulsion
Across a Period: Atomic Radius
Decreases. Why? Greater Positive Nuclear Charge
Down a Group: Atomic Radius
Increases. Why? 1) Increased number of energy levels 2) Increased electron repulsion
Group 1
Alkali Metals
Group 2
Alkaline Earth Metals
Group 3
Transition Metals
Group 4
Halogens
Group 5
Noble Gases
Group 6
Metalloids
Ionic Radius: Cations
Positive charge, lost electrons, gets smaller
Ionic Radius: Anions
Negative charge, gained electrons, gets bigger
Melting/Boiling Point
Highest in the middle of a period