Chapter 2

Question 1

Started the modern era of chemistry

Answer 1

John Dalton

Question 2

Dalton’s Atomic Theory

Answer 2

1. Elements are comprised of individually building blocks called atoms.
2. Compounds are composed of more than one element.
3. Chemical reactions rearrange atoms in chemical compounds; they do not create or destroy matter (atoms).

Question 3

Atoms are alike in (1) _______, (2) ________, and (3) ________.

Answer 3

(1) size
(2) mass
(3) chemical properties

Question 4

Law of Definite Proportions

Answer 4

elements combine in only one ratio

Example: NaCl, MgBr2, CaO

Question 5

Law of Multiple Proportions

Answer 5

elements can combine in different ratios

Example: CuCl, CuCl2, CuCl3

Question 6

Most basic unit of an element

Answer 6

Atom

Question 7

Used cathode tube to discover the nature of the electron, led to the “Plum Pudding Model”

Answer 7

JJ Thompson

Question 8

The “Plum Pudding Model” was disproved by which experiment?

Answer 8

Rutherford’s Gold Foil Experiment

Question 9

Who proved the neutron?

Answer 9

James Chadwick

Question 10

Cation

Answer 10

Lost electrons 
(Resulting charge became more positive. Think: cats have paws)

Question 11

Anion

Answer 11

Gained electrons
(Resulting charge became more negative.)

Question 12

Isotope

Answer 12

same number of protons and electrons but a different number of neutrons

Question 13

Average Atomic Mass

Answer 13

masses of the elements are determined by their natural abundances

Question 14

1 amu = ______________

Answer 14

1/12th of a Carbon-12 atom

Question 15

Ion

Answer 15

charged atom or group of atoms

Question 16

Ionic compounds

Answer 16

held together by electrostatic forces

Question 17

Empirical Formula

Answer 17

lowest whole number ratio of atoms

Question 18

Molecular Formula

Answer 18

ACTUAL formula