Chapter 2 History Of The Atom

Question 1

Atom – from the Greek “atomos

Answer 1

indivisible, the smallest particle of an element that retains the chemical nature of the element

Question 2

Law of Conservation of Mass

Antoine Lavoisier, late 1700s
Father of Modern Chemistry

Answer 2

In a chemical reaction, matter is neither created nor destroye

Question 3

Law of Definite Proportions

Joseph Proust, 1794

Answer 3

All samples of a given compound regardless of their source or how
they were prepared have the same proportions of their constituent
elements. (c. 1794

Question 4

Law of Multiple Proportions

John Dalton

Answer 4

When two elements (element A and B) form different compounds, the
masses of one element (element B) that combines with a certain mass
of the first element can be expressed as the ratio of small whole numbers.

Question 5

Atomic Theory, 1808

Answer 5

All matter is made of atoms, which are tiny indestructible particles. Subatomic particles

All atoms of a given element are identical, both in mass and properties, which distinguishes it from atoms of other elements. Isotopes

Compounds are formed from the combination of atoms in simple, whole-number ratios. Non-stoichiometric compounds

Atoms of one element cannot be changed into atoms of another element. In a chemical reaction, atoms are separated and recombined to form new compounds. Nuclear decay

Question 6

The Electron, 1897

J.J. Thomson
1906 Nobel Prize, physics

Answer 6

charge-to-mass ratio of

– 1.76 x 108 coulombs per gr

Question 7

The Oil Drop Experiment, 19

Answer 7

Robert Millikan
1923 Nobel Prize
physics

Question 8

Nuclear Theory

Answer 8

Most of the atom’s mass and all of its positive charge are contained within the core called the nucleus

Most of the volume of an
atom is empty space,
throughout which the electron
is dispersed.

The atom is electrically
neutral, therefore the number
of protons and electrons
must be equal.

Question 9

The Neutron, 1932

Answer 9

James Chadwick

1935 Nobel Prize physics

Question 10

Atomic number, Z

Answer 10

The number of protons in an atom

Question 11

Mass number, A

Answer 11

The sum of the number of protons and neutrons

Question 12

Isotopes

Answer 12

Atoms with the same number of protons but different number of neutrons

Question 13

Ions

Answer 13

An atom or group of atoms that is charged

Question 14

Cations

Answer 14

A positively charged ink due to a loss of electrons

Question 15

Anion

Answer 15

A negatively charged ion due to a gain of electrons

Question 16

Mass number

Answer 16

Proton plus neutrons

Question 17

Atomic mass

Answer 17

The weighted average mass of an elements atom which accounts for isotopes and relative abundance

Question 18

Family

Answer 18

Column of elements(group)

Question 19

Period

Answer 19

Row of elements

Question 20

Groups 1:

Groups 2:

Answer 20

Alkaline metals: very reactive with h2p

Alkaline earth

Question 21

Groups 3-12

Answer 21

Transition metals

Question 22

Group 17

Answer 22

Halogens

Question 23

Group 18

Answer 23

Noble has

Question 24

Metals

Answer 24

Good conductor
Malleable: thin sheet
Die tile: thin wire forms cation, lose electrons

Question 25

Metalloids

Answer 25

Intermediate properties

B,Si, Ge,As, Sb, Te, At

Question 26

No metals

Answer 26

Poor conductors

Form anions or share electrons

Question 27

Mole

Answer 27

The amount of substance that contains the same number of entities as there are atom

Question 28

Molar mass

Answer 28

The mass of one Moo is substance

For elements the molar mass is equal to its atomic mass

For compounds the molar mass is the sum of the elements