The Periodic Table and Periodic Law Chapter 6 The Periodic Table and Periodic Law

6.1 Development of the Modern Periodic Table 1. Antoine Lavoisier (1743-1794) Compiled a list of all known elements 23 know elements at that time

6.1 Development of the Modern Periodic Table 2. John Newlands (1837 – 1898) Law of Octaves = every 8th element repeats a common set of properties Not widely accepted due to missing elements and his use of musical terminology

6.1 Development of the Modern Periodic Table 3. Dimitri Mendeleev (1834 – 1907) 1869 he published 1st periodic table by atomic mass and chemical properties Predicted the properties of missing elements: scandium, gallium, and germanium

6.1 Development of the Modern Periodic Table 4. Henry Moseley (1887 – 1915) 1913 equated number of protons with atomic number Reordered the P.T. by atomic # fising some of the elements that didn’t fit their spots based on properties

6.1 Development of the Modern Periodic Table 5. periodic law: The repeating pattern of chemical and physical properties when elements are arranged by atomic number

6.1 Development of the Modern Periodic Table 6. organization Groups/families: Columns of/on the P.T.

6.1 Development of the Modern Periodic Table Periods: Rows of/on the P.T.

6.1 Development of the Modern Periodic Table Main group/representative elements: Elements in groups where the number is followed with an “A” Have a wide range of chemical and physical properties

TABLE: Metals: Location = to the left of the staircase except H Properties = shiny, mostly solids, good conductors of heat/electricity, and malleable/ductile Examples = copper (Cu), gold (Au), iron (Fe)

TABLE: Nonmetals: Location = to the right of the staircase plus H Properties = brittle (when solid), mostly gases, poor conductors Examples =helium (He), oxygen (O), Iodine (I)

TABLE: Semimetals/metalloids: Location = along the staircase except Al Properties = properties of both metals and nonmetals Examples = B, Si, Ge, As, Sb, Te, Po, and At

TABLE: Alkali metals: Location = 1A (except H) Valence e- and charge = 1 ve- and +1 Properties = highly reactive; soft, gray solids

TABLE: Alkaline Earth metals: Location = 2A Valence e- and charge = 2 ve- and +2 Properties = very reactive; soft, gray solids

TABLE: Transition metals: Location = “B” groups Valence e- and charge = 2 ve- and +1,+2,+3 or +4 Properties = shiny, good conductors, can be polyvalent (means can have more than 1 possible charge)

TABLE: Halogens: Location = 7A Valence e- and charge = 7 ve- and -1 Properties = highly reactive; can be solids, liquids or gases

TABLE: Noble Gases: Location = 8A Valence e- and charge = 8 ve- and no ion formation Properties = extremely unreactive, gases, full outer energy level

TABLE: Rare Earth metals: Location = Bottom double rows Valence e- and charge = 2 ve- Properties = often used as phosphors (elements that emit light when struck by electrons) Also know as the “Lanthanides” and “Actinides”

6.2 Classification of the Elements 1. Valence Electrons = electrons in the highest principle energy level Within a period: elements have the same # of energy levels as the period # where they are found Within a group: elements have the same # of ve-s as their group (representative elements) and all transition and rare earth elements have 2 ve-s

6.2 Classification of the Elements 2. s, p, d, f blocks s block: group 1A, 2A, hydrogen and helium p block: groups 3A-8A but not He d block: transition elements; all have 2 ve-s because d’s are 1 energy level behind f block: rare earth elements; all have 2 ve-s because f’s are 2 energy levels behind

6.3 Periodic Trends Periodicity: The repeating nature of the properties of the elements creating common groups (periodic law)

6.3 Periodic Trends Atomic Radius DEFINITION: relative size; distance from the center of the atom to the edge of the e- shell PERIOD TREND: GROUP TREND:

6.3 Periodic Trends Ionic Radius DEFINITION: relative size; distance from the center of the ion to the edge of the e- shell PERIOD TREND: GROUP TREND:

6.3 Periodic Trends Ionization Energy DEFINITION: the energy required to remove an electron from a gaseous atom PERIOD TREND: GROUP TREND:

6.3 Periodic Trends Electronegativity DEFINITION: the ability of an atom to attract electrons while in a chemical bond PERIOD TREND: GROUP TREND:

6.3 Periodic Trends Lower Left Large (atomic/ionic radius) Lower Left Low (ionization E./electroneg.)