Chem: Unit 2 Test Review

Front 1

Created the plum-pudding (oatmeal & raisins) model of atoms

Back 1

JJ Thomson

Front 2

Performed an oil drop experiment to study electrons in 1910

Back 2

Robert Millikan

Front 3

Discovered neutrons using alpha particle bombardment

Back 3

James Chadwick

Front 4

First said that matter was made of smaller particles called atoms

Back 4

Democritus

Front 5

Used a cathode ray tube in his experiment in 1897

Back 5

JJ Thomson

Front 6

Used scientific experimentation and summarized the work of others

Back 6

John Dalton

Front 7

Developed the Atomic Theory in 1806

Back 7

John Dalton

Front 8

Discovered the nucleus as a tiny, dense structure surrounded by mostly empty space

Back 8

Ernest Rutherford

Front 9

Discovered the first subatomic particle: the electron

Back 9

JJ Thomson

Front 10

Found that each element has a unique atomic number using X-rays

Back 10

Henry Moseley

Front 11

Performed experiment using gold foil and a radioactive source (1906)

Back 11

Ernest Rutherford

Front 12

Said that electrons orbit the nucleus in circular paths and that they have different energy levels, a pioneer in quantum mechanics (1913)

Back 12

Neils Bohr

Front 13

He rejected Democitus’ idea of atoms

Back 13

Aristotle

Front 14

Found the exact charge of the electron and its approximate mass (1/1,840th the mass of a proton)

Back 14

Robert Millikan

Front 15

Used emission spectra to study energy and electrons(quantum levels)

Back 15

Neils Bohr

Front 16

Master of Measurement, Law of Conservation of mass, late 1700s

Back 16

Antoine Lavoisier

Front 17

Father of Scientific Method, master data collector, 1st chemist, 1600s

Back 17

Robert Boyle

Front 18

Discovered “air” was actually many “different airs”, discovered oxygen

Back 18

Joseph Priestly

Front 19

How and why are Thomson’s and Rutherford’s models different?

Back 19

Thomson’s model suggested that the atom was like a ball of positively charge with the negatively charge electrons uniformly dispersed throughout. It was developed before the nucleus had been discovered. Rutherford’s model shows the tiny positive nucleus in the center with the electron orbiting it with most of the atom being empty space.

Front 20

What are the three subatomic particles and what charged do they have?

Back 20

Protons- positive, neutrons-neutral, electron-negative

Front 21

What two particles are found in the nucleus of an atom?

Back 21

Protons and neutrons

Front 22

What is an isotope? Give two examples.

Back 22

Atoms of the same element with a different number of neutrons Examples: Carbon-12 & Carbon-14, Uranium-235 & Uranium-238

Front 23

What does the atomic number correspond to in an atom?

Back 23

The number of protons in the nucleus

Front 24

Why are electrons not included in determining the mass number?

Back 24

The mass of an electron is so small it is not counted. Their mass is about about 1/2000th the mass of a proton or neutron.

Front 25

Explain why the atomic masses of elements on the periodic table are not whole numbers.

Back 25

The atomic mass on the periodic table is the average mass of all the atoms including all of the different isotopes of the element.

Front 26

What do the numbers 7 and 3 on the following nuclear symbol for Lithium correspond to?

Back 26

The 7 is the mass number which is the protons plus neutrons. The 3 is the atomic number which is the number of protons

Front 27

How would you determine the number of neutrons?

Back 27

You would subtract the atomic number (3) from the mass number (7). 7 – 3 = 4 neutrons

Front 28

In their elemental or natural state atom are neutral. How do the number of electrons and protons compare in this state?

Back 28

The number of protons and electrons are equal in neutral atoms.