⭐️History of Atoms Flashcards
(49 cards)
Aristotle
Matter is continuous, it’s not made of anything smaller
Boyle
Believed in the atomic nature of elements, no proof, first scientist with quantitative values for gases (Father of Chemistry) THE WORLD IS MADE OF LIL BOILS (atoms)
Dalton
Logical explanation for the existence of atoms
Lavoisier (used by Dalton)
Conservation of mass and matter 2 H2O>2 H2+O
Proust (used by Dalton)
Law of definite proportions-compounds will always have same ratio of elements by mass H20>2g:16g PROUST IS PROUD OF HIS DEFINITE PROPORTIONS
Dalton’s atomic theory (3 rules)
- All matter is made of atoms and cannot be broken down (atoms look like cannonballs)
- Atoms of the same element are identical (did not account for isotopes)
- Atoms of different elements combine in simple ratios by mass to compound
COMPOUNDS CANNONBALLS AND IDENTICAL ATOMS
Dalton’s law of multiple proportions
Compares 2+ different compounds with the same elements, 1 element stays the same, another changes by a multiple which make a diff compound
CO>CO2:
C(12g)O(16g)>C(12g)O2(32g)=16:32 or 1:2
Democratives
The world is made up of empty spaces and tiny particles
Gay-Lussac
COMBINING GASES under the same conditions “the volumes of gasses + their properties are in simple whole #’s” N2+2O2>2NO2…forming compounds
Avogadro
Explained Gay-Lussac using Dalton, = volumes of gases, under same conditions (in same container) contain the same # of particles (molecules)…when they’re combined to make a compound. Bc 4 avocados+4 avocados=4 bowls of guacamole with 2 avocados in each bowl
Who discovered the 1st electron and how?
Thomson, determined electrons mass to charge ratio (cathode rays (-) deflected to positive magnet instead of anode (+) )
Millikan
Oil-drop test, accurately determined electrons charge
What can you conclude between Thomson and Millikans discoveries?
Charge of electron is negative, mass of electron=1/1837th that of the lightest element
Who discovered the 1st proton and how?
Thomson, filled cathode tube with hydrogen; rays (protons) move from anode (+) to cathode (-), so charge proton=+, mass proton= 1 amu
Who discovered the 1st neutron and how?
Chadwick, bombarded berylium (Be) atoms w alpha particles, helium (He) released high energy particles w no charge, so charge neutron=0, mass=proton=1 amu
Thomson’s model of atom
Plumpudding (chocolate chip/m&m cookie)
People who contributed to the discovery of isotopes
Thomson, chemically alike but diff masses…Mosely, each element has its own wavelength which corresponded to an atomic#=#of protons MOSELY DISCOVERED HOW MANY PROTONS THERE ARE, BUT THOMSON WAS ALL LIKE, IF THEY THE SAME Y THEY GOT A DIFFERENT MASS?
What is an isotope?
Different #of neutrons than protons. Atomic# (protons) must stay the same. Mass can change, due to neutron change. (N+P=atomic mass)
Placement of atomic mass, atomic #, and element on p table
Top=mass
Center=Scientific name
Bottom=#
1 amu is ___ the mass of C-12
1 amu is 1/12th the mass of C-12
Mass spectrometer
Device used to measure different masses (isotopes) for an element (side note: in a non-isotope element, atomic #•2=mass because protons+neutrons=mass and it has the same #of protons/neutrons so u don’t need a spectrometer to know that)
Calculating average mass
percentage (don’t move decimal)•number + p•n + p•n divided by 100….unit is in SIG FIGS and AMU
Rutherford
Gold-foil experiment POSITIVE NUCLEUS atom is mostly empty space (98% of alpha plus passes thru the Au foil undeflected). Atoms have a small, dense, positive nucleus (2% hit the foil/were deflected) HE WAS POSITIVE THAT HE HAD A GOLD FORD
Becquerel
Uranium exposed photographic film BECCA! STOP EXPOSING MY PHOTOGRAPHIC FILMS
