gen chem 2

• Limit of cutting a paper : Invisible particle
• "laughing philosopher" Democritus
• Everything is composed of indivisible particles called ATOMS -Democritus
• 1807 atomic model: John Dalton - Solid sphere model
• 1897 atomic model: Joseph John Thompson - Plum pudding model
• 1911 Atomic Model: Ernest Rutherford - Nuclear Model
• 1913 atomic model: Niels Bohr - Planetary Model
• 1926 atomic model: Erwin Schrodiñger - Quantum Model
• Law of conversation of mass by Antoine Lavoisier. In a chemical reaction, no change in mass takes place. The total mass of the products is equal to the total mass of the reactants.
• Law of definite proportions by Joseph Proust. A compound always contains the same constituent elements in a fixed or definite proportion by mass
• Law of multiple proportions by John Dalton. If two elements can combine to form more than one compound, the masses of one element that will combine with a fixed mass of the other element are in a ratio of small whole numbers.
• JJ thompson "electron" - Plum pudding model
• E Rutherford "proton" - Gold foil experiment
• James Chadwick "neutron" - Bombardment of Berrylium atom from radioactive decay of Polonium
• Atomic number (Z) = number of protons in nucleus
• Mass number (A) = number of protons + number of neutrons

  Atomic number (Z) + number of neutrons
• Ion is an atom or group of atoms that carries electric charge.
• Cation type of electron. positive, loses electron
• anion a type of electron. negative charged, gains electron
• Octet rule. It states that atom loses, gains, or shares electron to fill their outermost energy shell with 8 valence electrons except H and He atoms; as well as metals.
• Covalent bond. sharing of electron
• Ionic bond. When an atom loses or gains electrons, it becomes a charged particle (ion)
• Isotope. Certain atom with the same atomic number but has different mass number
• 2 categories of isotope: stable and unstable
• There are 254 existing isotopes.
• Hydrogen. the only element whose isotopes have unique names.
• C-14 allows the accurate dating of archaeological artifacts.
• Carbon used to handle charcoal from fire
• Carbon. 4th most abundant element in the universe and the 15th most abundant element in the Earth’s crust.
• Carbon was discovered as a novel element in 1722 by Antoine Ferchault de Réaumur
• Co-60 is used for sterilization of surgical instruments
• Its compounds are known as cobalt blue used to color pottery and glass.
• Cobalt is transition metal and was discovered in pure form in 1735. It is essential part of vitamin B12
• Cobalt. It also stimulates the production of red blood cells and is widely used to treat anemia
• H-2 (Deuterium)is used as a refrigerant in cooling systems and cryogenics.
• In 1766, henry Cavendish isolated hydrogen and identified it as a unique element.
• Hydrogen gas was first created by Robert Boyle and others
• H1 (Protium) H2(Deuterium) H3(Tritium)
• Cobalt have 28 isotopes but CO-60 the only stable
• Iodine was discovered by Bernard Courtois in 1811.