Lect 11/30 Flashcards
What did Antoine Lavoisier do?
Developed Law of Mass Conservation
What did Democritus do? What is he know for?
Developed Ancient Atomic Theory; tried to starve himself to death on a mountain
What year did Antoine Lavoisier develop his theory?
1789
What is the modern atomic theory? (4 parts)
1) All chem substances composed of uncuttable atoms
2) All atoms of one type are identical to each other
3) law of mass conservation; # and types of atoms are the same before and after a reaction, only change in how they are attached to one another.
4) Proust’s law of definite comp
What is Joseph Proust’s Law of Definite Proportions?
A given chemical compound always contains it elemental components in a fixed ratio by mass
What did John Dalton do?
Developed modern atomic theory
What did JJ Thomson do?
Discovered electrons
What year did JJ Thomson make his discovery?
1895
What model did JJ Thomson develop?
Plum pudding model of the atom
What 2 adjectives are used to describe metals? What do they mean?
- malleable: ability to be hammered out of shape
- ductile: ability to be stretched into a thin wire
What is the most malleable metal?
Gold
What are 2 ways of telling metals from nonmetals?
appearance; looks like metal
ability to conduct heat and/or electricity
What experiment did Rutherford conduct? What was the result?
Gold foil experiment; atom is mostly empty space with a tiny, dense, positively charged nucleus.
What did Rutherford Bohr develop? What did it look like?
Neil’s Bohr model; electrons orbit around nucleus (solar system model)
What did Erwin Schrodinger develop?
Quantum mechanical model of atom
What did James Chadwick do?
discovered neutron in the nucleus
What is atomic number?
number of protons in the nucleus
What is the atomic mass number?
Number of protons AND neutrons in the nucleus (# of nucleons)
What 2 things did Henry Moseley do?
- Z is the identity of the atom type.
- coined the word isotopes
What are isotopes?
2 or more atoms with the same Z but different A
What does A stand for, Z?
A = atomic mass number
z = atomic number
What did Wilhelm rontgen do?
Discovered radioactivity
What is radioactivity?
spontaneous decay of unstable parent nuclei into daughter products.
What makes an atom unstable?
number of neutrons > number of protons
What is atomic mass?
weighted average of each of the (naturally occuring) isotopes
