A.E.Beguyer de Chancourtois Henning Brand Johann Dobereiner jean baptiste dumas Brand- discovered phosphorus. Johann-atomic weights  Leopold Gmelin Max von Pettenkofer A.E.Beguyer de Chancourtois

Dmitri Mendeleev A Russian chemist, considered to be the “Father of the Periodic Table” Grouped up discovered elements based on measureable properties: Density, appearance, and melting point Scientists have taken all of the elements and tried to group them together based on their properties.

The “Periodic” Table Mendeleev saw that when the elements were arranged in order of increasing atomic mass, those that had similar properties occurred in a repeating pattern. This pattern was periodic He found that this pattern repeated every 7 elements

Dashes represent missing elements, gaps in the pattern Dashes represent missing elements, gaps in the pattern. He left them open and decided that they just havnt been discovered yet

The Periodic Table Elements are organized by their properties Horizontally (Row or Period) – increasing atomic number (number of protons and electrons) Your senses tell you things. When you touched the liquid, you expected it to get wet. When you smelt the beaker, you expected to get a smell. The location of an element on the periodic table is just like your senses: it tells you things.

The Periodic Table Vertically (group or family) – elements with similar chemical properties Family Number is the number of valence electrons Your senses tell you things. When you touched the liquid, you expected it to get wet. When you smelt the beaker, you expected to get a smell. The location of an element on the periodic table is just like your senses: it tells you things.

Transition Metals Groups/Families Alkali Metals Alkaline Earth Metals Boron Group Carbon Group Nitrogen Group Oxygen Group Halogen Group Noble Gases Alkali Metals react explosively with water, have similar bonds cowar Transition Metals

Metals All solid except Hg (mercury) Shiny, good conductors of electricity and heat Ductile (can be made into a wire) Malleable (can be pounded into sheets) Mercury – only liquid metal at room temperature. Thermostats, found in fatty fish that lived in water that was contaminated by coal burning plants Iron – horseshoes, ancient tools, modern-day tools, Zirconium – from mineral zircon. Used as jewelry…. Diamond like

Nonmetals Opposite of metal properties Brittle Not malleable Not ductile Poor conductors Chlorine – pale yellow gas that was used as mustard gas during WW1 to kill soldiers, today used for cleaners, pool, bleach, etc Phosphorus – white colored, most dangerous, used for matches Sulfur – one of few NATURAL occurring elements. Sulfur componds is responsible for giving onions and garlic their smell

Metalloids 7 of them Properties are a mix of metals and nonmetals Economically important due to unique properties Boron – extremely hard in pure form, but extremely brittle. Boric acid is Found in Silly Putty, gives it its elastic texture Arsenic – poisonous, semiconductor with gallium to produce high speed circuits for supercomputers and cell phones Silicon – Found in, TV, sand, silicone gels. Projectors, watches, etc.

92 natural elements, the rest are synthetic The world is made up of matter, which make up elements. Examples:

Atoms Atoms are the basic building blocks of matter Ask students to draw what they think an atom looks like on their notes

Electrons – negative (-) Protons – positive (+) Neutrons – neutral (0) Electrons – negative (-) Review periodic table

Atomic Number - # of protons and electrons Symbol – Symbol of element Name – Name of element Atomic Mass – average weight (protons and neutrons)

Mass Number - (minus) Atomic Number = # of Neutrons = # of Protons = # of Electrons Mass Number - (minus) Atomic Number = # of Neutrons