scientists Flashcards
What did democritus belive about the atom
they could not be cut
Atoms have different sizes, are in constant
motion, and separated by empty space
What did aristotle believe
He thought that all matter was made up of 4 elements
earth, wind, fire water,
What did john dalton believe
Atoms cannot be created, destroye d odevided
the atom of an elemnet cannot convert into another element
all atom of the same element have the same properties (mass, size)
atoms of diff elements combine to form compounds
what did lavoiser discover (law…)
law of conservation of amss
what did proust discover (law..)
law of composition
(each atom has a particular combinnb capacity)
In what ways was Dalton wrond
The atom is divisible
what did jj thomson discover
Electrons
saw that a current emitted negativly charged particles when passed through a gas
Since the gas was neutral then the negative particles must have pos counterparts
What is the plum pudding model
Made by jj thomson
Says that ataoms are made from a pos charged substance with negative electrons scattered in it.
What was ruthorfords experiment, what did it find
shooting alpha particles through gold foil and measuing the angle.
Most alpha particles passed through normally, some of them bounced back.
This meant that there was something positibly charged in the middle
This happened at that center of the atom
what were the limitations of ruthorfords exp
If the nucleus is made up of all pos then how does it hold togethor
did not explain the mass of an atom (nautron not discovered yet)
At the time they thought that an electron orbiting must continuoously emit ratiation
What did james chadwich discover
Found neutrons
bombarded beryllium with alpha particles,
neutral ray was emitted
What did bohr discover
Electron exist in orbits
electron does not radiate when in orbit
electrons can jump between levels by absorbing and emittinng photons
Order of scientists on the atom
Democritus, aristotle, dalton, thosmson, ruthorford,bohr. chadwick
Which scientists helped create the periodic table (4)(Jd,Ja,DM,HM)
Johann dobereienr, - law of triads
John alexander newlands - law of octaves
dimitri mendeleev - arranged elements acording to atm mass
Henry moseley - arranged according to atm num
