Science W1 Flashcards
is a Greek Philosopher who
began to search for a description
of matter.
Democritus
an English Chemist who performed a
number of experiments that
eventually led to the acceptance
of the idea of atoms
He deduced that all elements are
composed of atoms.
John Dalton
Democritus named the smallest piece of
matter; what?
Atomos, meaning “not
to be cut”.
Atoms of the same elements are
exactly alike.
Atoms of different elements are
different.
Compounds are formed by the
joining of atoms of two or more
elements.
John Dalton’s Solid Sphere Model
an
English Scientist, provided the
first hint that an atom is made of
even smaller particles.
He also introduced the idea of the
negatively charged particle called
“electron”.
Joseph John Thomson
Atoms were made from
positively charged substances
with negatively charged electrons
scattered about, like raisins in a
pudding.
J.J. Thomson’s Plum Pudding Atomic
Model
He reasoned that all atoms are
positively charged particles
that are contained in the
nucleus.
Negatively charged particles
were scattered outside the
nucleus around the atom’s
edge.
Ernest Rutherford’s Nuclear Model
He placed each electron in a
specific energy level.
Electrons move in definite
orbits around the nucleus, much
like a planet circles the sun
(solar system).
These orbits, or energy levels
are located at certain distances
from the nucleus.
Niels Bohr’s Planetary Model
Electrons are moving
around the nucleus.
Assumed that orbits
don’t have to be
spherical but can also
be elliptical.
Arnold Sommerfeld’s atomic Model
A Physicist and a Biologist, was
considered the Father of
Quantum Mechanics
Erwin Schrodinger
A space in which electrons are likely
to be found.
Electrons whirl about the nucleus
billions of times in one second.
They are not moving around in
random patterns.
The location of electrons depends
upon how much energy the electrons
have.
Erwin Schrodinger’s Quantum
Mechanical Model of Atom
