Chem Chapter 2

Front 1

Law of Definite Proportions

Back 1

All samples of a given compound have the same proportions of their constituent elements.

Ex: decomposition of water results in 16g O and 2g H. Mass ratio: 16g/2g= 8 or 8:1

Front 2

Law of Multiple Proportions

Back 2

When two elements (A and B) form two different compounds the masses of element B that combine with 1g element A can be expressed as a ratio of small whole numbers. Ex:

Mass O to 1g C in CO2 / Mass O to 1g C in CO=

2.67/1.33=2

Front 3

Atomic Theory

by John Dalton

Back 3

1. Each element is composed of tiny indestructible particles called atoms

2. All atoms of the same element have the same mass (incorrect)

3. Atoms combine in simple, whole-number ratios to form compounds

4. Atoms of one element cannot change into atoms of another element

Front 4

Charge of the electron

Back 4

-1.60x10^-19 C

Front 5

Radioactivity

Back 5

The emission of small energetic particles from the core of certain unstable atoms

Front 6

Nuclear Theory

by Earnest Rutherford

Back 6

1. Most of the atom's mass and all of it's + charge is in the nucleus

2. Most of the volume of an atom is empty space through which tiny negatively charged particles are dispersed

3. There are as many electrons as protons to make an atom electrically neutral

Front 7

Mass ratio of protons to neutrons to electrons

Back 7

1:1:1/1840

Front 8

Isotopes

Back 8

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

Front 9

Mass number

Back 9

symbol: A

number of protons + number of neutrons

Front 10

Atomic number

Back 10

symbol: Z

equal to the number of protons

Front 11

Isotope notation

Back 11

A above Z to the left of Chemical symbol

Chemical symbol-A

Front 12

Cations

Back 12

positively charged atoms or particles

Front 13

Anions

Back 13

negatively charged atoms or particles

Front 14

Metals

Back 14

good conductors, malleable, ductile, often shiny, usually solid at room temp., tend to lose electrons

Front 15

Nonmetals

Back 15

poor conductors, tend to gain electrons

Front 16

Metalloids/Semiconductors

Back 16

intermediate conductivity, along the zigzag line. Ex: Silicon, Arsenic, Anitimony

Front 17

Main-Group Elements

Back 17

Columns 1A-8A

Front 18

Transition elements/Transition metals

Back 18

Columns 1B-8B (in the depression)

Front 19

Family/Group

Back 19

A column within the main-group regions

Front 20

Noble gasses

Back 20

Column 8A, mostly unreactive

Front 21

Alkali Metals

Back 21

Column 1A, highly reactive metals

form +1 ions

Front 22

Alkaline Earth Metals

Back 22

Column 2A, fairly reactive metals

form +2 ions

Front 23

Halogens

Back 23

Column 7A, very reactive nonmetals

form -1 ions

Front 24

Metals typically react to have the same number of electrons as _______

Back 24

The previous noble gas

Front 25

Nonmetals typically react to have the same number of electrons as _______

Back 25

The next noble gas

Front 26

Atomic Mass

Back 26

average mass of the isotopes that compose that element.

(% of isotope 1 x mass of isotope 1) + (% of isotope 2 x mass of isotope 2) + (% of isotope 3 x mass of isotope 3)...

Front 27

Finding abundance % from mass spectrometry chart

Back 27

% for one isotope/ sum of %'s from all isotopes x 100%

Front 28

Mole

Back 28

Abbreviated mol.

6.022x10^23 units

i.e. Avogadro's Number

Front 29

Duterium

Back 29

Hydrogen with one neutron

Front 30

Tritium

Back 30

Hydrogen with two neutrons

Front 31

Protium

Back 31

Hydrogen with no neutrons

Front 32

Transition element charges depend on _______

Back 32

The element or particles that they are attached to. Ex: FeCl2, Fe has 2+ charge, FeCl3, Fe has 3+ charge