Properties of Atoms and PT

 Democritus- said that all atoms are small hard particles  Aristotle- believed that you would never end up with a particle that could not be cut.

 1. All substances are made of atoms. Atoms are small particles that cannot be created divided or destroyed.  2. Atoms of the same element are exactly alike and atoms of different elements are different  3. Atoms join with other atoms to make new substances

 Thompson discovered electrons  Rutherford- found the nucleus  Bohr- improved the atomic theory with orbitals

 Quarks Quarks

 Bohr’s idea- electrons move around the nucleus in energy levels  Electrons can jump from one energy level to another.

 Schrodinger and Heisenberg came up with quantum mechanics model-the exact path of an electron cannot be predicted. AKA electron cloud theory

 Mendeleev wrote the first periodic table  18 families or groups going vertically  7 periods or series going horizontally  Based on atomic masses

 Moseley determined the number of protons the atomic number as the basis for a periodic table  Periodic law states that the repeating chemical and physical properties of elements change periodically with the element’s atomic number

 Metals  Nonmetals  Metalloids

 Each element has a one or two letter symbol which stands for the name of the element. First letter is capitalized the second is in small case

 A. Group contains: Metals  B. Electrons in outer level: 1  C. Reactivity: very reactive  D. Other shared properties: softness, color of silver, low density, shininess

 A. Group contains : Metals  B. Electrons in outer level: 2  C. Reactivity: very reactive but slightly less than alkali metals  D. Other shared properties: color of silver, higher densities than alkali metals

 A. Group contains: Metals  B. Electrons in outer level: 1 or 2  C. Reactivity: less reactive than alkaline earth metals  D. Other shared properties: good conductors of electricity and current higher densities and melting points than group 1 and 2 metals

 A. Group contains: 4metals and 1 metalloids  B. Electrons in outer level: 3  C. Reactivity: reactive  D. Other shared properties: solids at room temperature

 A. Group contains: one nonmetal, 2 metalloids and 2 metals  B. Electrons in outer level: 4  C. Reactivity: varies among elements  D. Other shared properties: solids at room temperature

 A. Group contains: 2 nonmetals, 2 metalloids and 1 metal  B. Electrons in outer level: 5  C. Reactivity: varies among the elements  D. Other shared properties: most are solids at room temperature

 A. Group contains: 3 nonmetals, 1 metalloids, 1 metal  B. Electrons in outer level: 6  C. Reactivity: Reactive  D. Other shared properties: All but oxygen are solids at room temperature

 A. Group contains: nonmetals  B. Electrons in outer level: 7  C. Reactivity: very reactive  D. Other shared properties: poor conductors, forms salts with alkali metals,

 A. Group contains: nonmetals  B. Electrons in outer level: 8,2  C. Reactivity: unreactive  D. Other shared properties: colorless, odorless, gases at room temperature