Scientists

Question 1

Dalton

Answer 1

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.

Question 2

Democritus

Answer 2

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.

Question 3

Aristotle

Answer 3

Empty space cannot exist.
* Matter is made of earth, fire, air, and water.

Question 4

Bohr

Answer 4

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

Question 5

de Broglie

Answer 5

hypothesized that particles, including electrons,
could also have wavelike behaviors.
The de Broglie equation predicts that all moving
particles have wave characteristics.

Question 6

Heisenberg

Answer 6

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.

Question 7

Schrödinger

Answer 7

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.

Question 8

Pauli

Answer 8

The Pauli exclusion principle states that a
maximum of two electrons can occupy a single
orbital, but only if the electrons have opposite
spins.

Question 9

Hund

Answer 9

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

Question 10

aufbau

Answer 10

The aufbau diagram can be used to write correct
ground-state electron configurations for all
elements

Question 11

Lavoisier

Answer 11

compiled a list of all the known elements of the
time.
He compiled the elements in one list containing 33
elements in 4 categories

Question 12

Newlands

Answer 12

noticed when the elements were arranged by
increasing atomic mass, their properties repeated
every eighth element.

Question 13

Meyer and
Mendeleev

Answer 13

both demonstrated a connection between atomic
mass and elemental properties

Question 14

Moseley

Answer 14

rearranged the table by increasing atomic number,
and resulted in a clear periodic pattern

Question 15

Le Châtelier

Answer 15

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

Question 16

Henry’s

Answer 16

at a given temperature the solubility of a gas in a
liquid is directly proportional to the pressure of the
gas above the liquid

Question 17

Crookes

Answer 17

Cathode ray

Question 18

Thomson’

Answer 18

discovered electron, plum pudding model

Question 19

Marie and Pierre
Curie

Answer 19

discovered that some elements
(the radioactive elements

Question 20

Rutherford

Answer 20

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

Question 21

Chadwick

Answer 21

discovered the neutron and measured its mass

Question 22

Graham

Answer 22

the rate of diffusion or of effusion of a gas is
inversely proportional to the square root of its
molecular weight.

Question 23

Dalton

Answer 23

the total pressure exerted is equal to the sum of
the partial pressures of the individual gases.

Question 24

Pascal

Answer 24

pressure change at any point in a confined
incompressible fluid is transmitted throughout the
fluid such that the same change occurs everywhere

Question 25

Boyle

Answer 25

pressure of a given mass of an ideal gas is inversely
proportional to its volume at a constant
temperature.

Question 26

Charles

Answer 26

the volume of an ideal gas at constant pressure is
directly proportional to the absolute temperature.

Question 27

Gay-Lussac

Answer 27

the pressure of a given mass of gas varies directly
with the absolute temperature of the gas

Question 28

Avogadro

Answer 28

equal volumes of gases at the same temperature
and pressure contain equal numbers of molecules

Question 29

Hess

Answer 29

regardless of the multiple stages or steps of a
reaction, the total enthalpy change for the reaction
is the sum of all changes