Scientists Flashcards
Dalton
Matter is composed of extremely small
particles called atoms.
* Atoms are indivisible and indestructible.
* Atoms of a given element are identical in
size, mass, and chemical properties.
* Atoms of a specific element are different
from those of another element.
* Different atoms combine in simple wholenumber ratios to form compounds.
* In a chemical reaction, atoms are separated,
combined or rearranged.
Democritus
Matter is composed of atoms, which move
through empty space.
* Atoms are solid, homogeneous,
indestructible, and indivisible.
* Different kinds of atoms have different sizes
and shapes.
* Size, shape, and movement of atoms
determine the properties of matter.
Aristotle
Empty space cannot exist.
* Matter is made of earth, fire, air, and water.
Bohr
Model of the Atom
* Hydrogen’s single electron is in the n = 1
orbit in the ground state.
* When energy is added, the electron moves to
the n = 2 orbit.
* Each orbit was given a number, called the
quantum number
de Broglie
hypothesized that particles, including electrons,
could also have wavelike behaviors.
The de Broglie equation predicts that all moving
particles have wave characteristics.
Heisenberg
showed it is impossible to take any measurement of
an object without disturbing it.
The Heisenberg uncertainty principle states that it
is fundamentally impossible to know precisely both
the velocity and position of a particle at the same
time.
Schrödinger
treated electrons as waves in a model called the
quantum mechanical model of the atom.
equation applied equally well to elements other
than hydrogen.
The wave function predicts a three-dimensional
region around the nucleus called the atomic orbital.
Pauli
The Pauli exclusion principle states that a
maximum of two electrons can occupy a single
orbital, but only if the electrons have opposite
spins.
Hund
Hund’s rule states that single electrons with the
same spin must occupy each equal-energy orbital
before additional electrons with opposite spins can
occupy the same energy level orbitals
aufbau
The aufbau diagram can be used to write correct
ground-state electron configurations for all
elements
Lavoisier
compiled a list of all the known elements of the
time.
He compiled the elements in one list containing 33
elements in 4 categories
Newlands
noticed when the elements were arranged by
increasing atomic mass, their properties repeated
every eighth element.
Meyer and
Mendeleev
both demonstrated a connection between atomic
mass and elemental properties
Moseley
rearranged the table by increasing atomic number,
and resulted in a clear periodic pattern
Le Châtelier
Le Châtelier’s Principle was proposed in 1888 and
states that if stress is applied to a system at
equilibrium, the system shifts in the direction that
relieves the stress
Henry’s
at a given temperature the solubility of a gas in a
liquid is directly proportional to the pressure of the
gas above the liquid
Crookes
Cathode ray
Thomson’
discovered electron, plum pudding model
Marie and Pierre
Curie
discovered that some elements
(the radioactive elements
Rutherford
He described the atom as a tiny, dense, positively
charged core called a nucleus surrounded by
lighter, negatively charged electrons., the electrons
orbit the nucleus like planets orbiting around the
sun. . This model is sometimes known as the
planetary model of the atom.
alpha particles and thin gold foil
Chadwick
discovered the neutron and measured its mass
Graham
the rate of diffusion or of effusion of a gas is
inversely proportional to the square root of its
molecular weight.
Dalton
the total pressure exerted is equal to the sum of
the partial pressures of the individual gases.
Pascal
pressure change at any point in a confined
incompressible fluid is transmitted throughout the
fluid such that the same change occurs everywhere
