Atoms

what type of physics failed?

Newtonian mechanics

What type of physics explains how the “small world” works?

quantum mechanics

what was the main success of quantum mechanics?

wave-particle duality of matter

The word “atom” comes from the Greek word “atomos,” which means…

not cuttable

An atom is the smallest identifiable unit of a/an ____

element

An element is identifiable by…

its number of protons

____ determines the property of an atom

structure

What teacher and student were the first to propose that matter was composed of small, indestructible particles?

Leucippus and Democritus

“Nothing exists except what and what…”

atoms, empty space

Plato and Aristotle believed what two fundamental things about matter?

• matter had no smallest parts

• dif. things were composed of dif. proportions of fire, air, earth, and water

Who is the Father of Modern Chemistry?

John Dalton

What is part one of Dalton’s Atomic Theory?

Each element is composed of tiny, indestructable particles called atoms

What is part two of Dalton’s Atomic Theory?

All atoms of a given element have the same mass and other properties that distinguish them from the atoms of other elements

What is part three of Dalton’s Atomic Theory?

Atoms combine in simple, whole number ratios to form compounds

What is part four of Dalton’s Atomic Theory?

Atoms of one element cannot change into atoms of another element. In a chemical rxn, atoms only change the way that they are bound tg with other atoms.

Who conducted cathode ray experiments?

J. J. Thomson

Briefly define the cathode ray experiment and its discovery.

• Thomson placed particles (cathode rays) in a partially evacuated glass tube with a + and - pulse

• Found that particles traveled from - charged electrode (cathode) to positively charged electrode (anode)

• Discovered the electron (e-)

define electron.

a negatively charged, low mass particle that travels quickly and is present in all atoms

what is the charge per gram of electron?

-1.76 × 10⁸ coulombs/gram

which experiment discovered the charge of a single electron?

Millikan’s Oil Drop Experiment

what is the charge of a single electron?

-1.60 × 10^-19 Coulomb

who conducted the gold foil experiment?

Ernest Rutherford and students Hans Geiger and Ernest Marsden

the number of protons in an atom is known as…

atomic number (Z)

Rutherford and which student found that unaccounted atomic mass was due to neutrons?

James Chadwick

what are the 3 main subatomic particles?

protons, neutrons, electrons

what defines an element?

its number of protons

there are ____ groups and ____ periods in a PT.

18, 7

what are the patterns in a PT called?

periodic trends

what are the three puzzles of classical physics?

• atomic spectra

• black-body radiation/UV catastrophe

• photoelectric effect

the puzzles of ____ physics led to ____ ____

classical, quantum mechanics

what is the electromagnetic radiation spectrum in order from shortest to longest wavelength?

• x-rays

• ultraviolet

• visible light

• infrared

• microwave

• radio wave

what is the visible light spectrum from shortest to longest wavelength?

• violet

• blue

• green

• yellow

• orange

• red