Unit 4 Chem test Review

Question 1

Democritus contribution

Answer 1

-460 BC
-Gave us the term Atom

Question 2

Dalton

Answer 2

-Early 1800s
-Dalton’s theory 4 main points

Question 3

Who/what work did Dalton follow?

Answer 3

-Lavoisier, Law of conservation of Matter
-Proust, Law of Constant Composition

Question 4

Dalton’s theory 4 main points

Answer 4

-All Matter consists of tiny particles called Atoms

-Atoms are indestructible and unchangeable. A chemical reaction simply changes the way the atoms are grouped together.

-Elements are identified by their atoms. All atoms of a given element are identical, but they differ from those of any other element.

-When elements react, their atoms combine in
simple, whole-number ratios.

Question 5

How was Dalton wrong in his theory?

Answer 5

Atoms CAN be broken into smaller parts. Example-Subatomic particles

All atoms of a given element are NOT identical. Example-Different isotopes

Question 6

Benjamin Franklin

Answer 6

-Mid 1800s
-Found that there were two kinds of electrical charges
(+) and (-)

Question 7

Thomson Contributions

Answer 7

-Late 1800s
-ALL atoms contain tiny negatively charged subatomic particles, electrons.
-Plum pudding, or Chocolate chip cookie dough

Question 8

Thomson experiment

Answer 8

Cathode ray tube- Electrons travel from a negatively charged Cathode to a positively charged Anode.

Question 9

Millikan

Answer 9

-1900s
-Oil drop experiment
measured the charge and
mass of an electron.

Question 10

Becquerel/Curies

Answer 10

-Radiation given of from Elements: radium, polonium, and Uranium
-Discovered Radioactivity:-spontaneous emission of radiation from an
element.
The nature of an atom changes when it gives off radiation (energy).

Question 11

Rutherford experiment

Answer 11

Gold foil experiemnt, shot a beam of alpha particles at a sheet of gold foil, a few of the particles were deflected. He concluded that a tiny, dense nucleus was causing the deflections.

Question 12

Rutherford changes to the atomic theory

Answer 12

-Concluded that the atom’s mass is concentrated in a positive, dense center, nucleus.

-The light, negatively charged, electrons circulated around this nucleus, much like planets revolving around the Sun.

Question 13

Chadwick

Answer 13

Credited with the discovery of the neutron

Question 14

Bohr key changes

Answer 14

Electrons travel in definite energy levels (orbitals) instead of random motion
Model of the atom became a planetary model.
changes with electrons

Question 15

Schrodinger- based on

Answer 15

-mathematical equation to find
where electrons are mostly moving
-Concept of electron clouds=where an electron is
predicted to be 90% of the time

Quantum Mechanical Model

Heisenberg Uncertainty Principle

Question 16

Democritus atomic drawing

Answer 16

just a dot

Question 17

Thomson atomic drawing

Answer 17

plum pudding

Question 18

Rutherford atomic drawing

Answer 18

+ mass in the center with negative empty space on the outside

Question 19

Schrodinger atomic drawing

Question 20

Bohr atomic drawing

Answer 20

Planetary model, e- traveling on orbitals with protons and neutrons in the center

Question 21

atomic theory people in order from the very beginning to now

Answer 21

Democritus, Dalton, Franklin, Thomson, Millikan, Becquerel/Curies, Rutherford, Bohr, and Schrodinger