General Chemistry Chapter 2: Atoms, Molecules, And Ions

Front 1

Atomic Theory

Back 1

an explanation of the structure of matter in terms of different combinations of very small particles

Front 2

Atom

Back 2

an extremely small particle of matter that retains its identity during chemical reactions

Front 3

Element

Back 3

a type of matter composed of only one kind of atom

Front 4

Compound

Back 4

a type of matter composed of atoms of two or more elements chemically combined in fixed proportions

Front 5

Atomic Symbol

Back 5

a one- or two-letter notation used to represent an atom corresponding to a particular element

Ex.
O - Oxygen
He - Helium

Front 6

Law of Multiple Proportions

Back 6

elements in a compound are in fixed ratios of small whole numbers

Front 7

Structure of An Atom:
Nucleus

Back 7

the atom's core
-positively charged
-contains most of the atom's mass

Front 8

Structure of An Atom:
Neutron

Back 8

-located in the nucleus
-no charge
-mass equal to about proton

Front 9

Structure of An Atom:
Proton

Back 9

-located in the nucleus
-positive charge
-mass equal to about neutron

Front 10

Electron

Back 10

-located outside the nucleus
-negative charge
-mass much smaller than neutron or proton

Front 11

Mass Number

Back 11

the number of protons and neutrons in an atom

Ex. ²³NA

Front 12

Atomic Number

Back 12

the number of protons in an atom

Ex. ₁₁NA

Also, the Atomic Number identifies the element on the periodic table.

Front 13

Isotopes

Back 13

atoms who nuclei have the same atomic number (protons) but different mass numbers (neutrons)

Ex. Oxygen
99.759% oxygen-16
0.037% oxygen-17
0.204% oxygen-18

Front 14

Atomic Weight

Back 14

the average atomic mass for the naturally occurring element, expressed in atomic mass units (amu)

Front 15

Atomic Weight:
Isotopic Masses and Fractional Abundance

Back 15

Ex. Chromium, Cr

Mass--|Isotopic|Fractional
Number|--Mass--|Abundance-
--50--|49.9461-|0.0435----
--52--|51.9405-|0.8379----
--53--|52.9407-|0.0950----
--54--|53.9389-|0.0236----


49.9461amu x0.0435 = 2.17amu
51.9405amu x0.8379= 43.52amu
52.9407amu x0.0950 = 5.03amu
53.9389amu x0.0236 = 1.27amu
------------------ + _______
------------------- 51.99amu

Front 16

Periodic Table

Back 16

a tabular arrangement of elements in rows and columns, highlighting the regular repetition of properties of the elements

Front 17

Periodic Table:
Period

Back 17

the elements in any one horizontal row of the periodic table

Front 18

Periodic Table:
Group

Back 18

the elements in any one column of the periodic table

Front 19

Main Group Elements

aka

Representative Elements

Back 19

the A Groups of the Periodic Table

Front 20

Transition Elements

aka

Transition Metals

Back 20

the B Groups of the Periodic Table

Front 21

Inner-Transition Elements

aka

Inner-Transition Metals

Back 21

the two rows at the very bottom of the Periodic Table

Front 22

Lanthanides

Back 22

first row of the Inner-Transition Metals

Front 23

Actinides

Back 23

the second row of the Inner-Transition Metals

Front 24

Alkali Metals

Back 24

Group IA

soft metals that react easily with water.

Li - Lithium
Na - Sodium
K - Potassium
Rb - Rubidium
Cs - Cesium
Fr - Francium

Front 25

Alkaline Earth Metals

Back 25

Group IIA

reactive metals, but less reactive than alkali metals

Be - Beryllium
Mg - Magnesium
Ca - Calcium
Sr - Strontium
Ba - Barium
Ra - Radium

Front 26

Halogens

Back 26

Group VIIA

reactive non-metals

F - Fluorine
Cl - Chlorine
Br - Bromine
I - Iodine
At - Astatine

Front 27

Noble Gases

Back 27

Group VIIIA

unreactive monatomic elements.

He - Helium
Ne - Neon
Ar - Argon
Kr - Krypton
Xe - Xenon
Rn - Radon

Front 28

Metal

Back 28

a substance or mixture that has a characteristic luster, or shine, and is generally a good conductor or electricity and heat.

are solids at room temperature, except for mercury.

Front 29

Nonmetals

Back 29

does not exhibit the characteristics of of metal.

are usually gases (chlorine and oxygen) or solids (phosphorus or sulfur). Bromine is the only liquid non-metal.

Solid nonmetals are usually hard, brittle substances.

Front 30

Metalloids

or

Semi-Metals

Back 30

have both metallic and non-metallic characteristics.

are good semi-conductors; conduct electricity and heat at high temperatures.

B - Boron
Si - Silicon
Ge - Germanium
As - Arsenic
Sb - Antimony
Te - Tellurium
At - Astatine

Front 31

Chemical Formula

Back 31

a notation that uses atomic symbols with numerical subscripts to convey the relative proportions of atoms of different elements in a substance.

Ex. Al₂O₃

Front 32

Molecule

Back 32

a definite group of atoms that are chemically bonded together.

Front 33

Molecular Formula

Back 33

gives the exact number of different atoms of an element in a molecule.

Front 34

Polymers

Back 34

very large molecules that are made up of a number of smaller molecules repeatedly linked together.

Front 35

Monomers

Back 35

the small molecules that are linked together to form a polymer.

Front 36

Ion

Back 36

an electrically charged particle obtained from an atom or chemically bonded group of atoms by adding or removing electrons.

Front 37

Anion

Back 37

an atom that picks up an electron and becomes negatively charged.

Front 38

Cation

Back 38

an atom that loses an electron and becomes positively charged.

Front 39

Ionic Compound

Back 39

a compound composed of cations and anions.

Front 40

Organic Compounds

Back 40

molecular substances that contain carbon combined with other elements, such as hydrogen, oxygen and nitrogen.

Front 41

Hydrocarbons

Back 41

compounds containing only hydrogen and carbon.

Front 42

Inorganic Compounds

Back 42

composed of elements other than carbon.

Exceptions: carbon monoxide (CO), carbon dioxide (C0₂), carbonates, and cyanides.

Front 43

Chemical Nomenclature

Back 43

the systematic naming of chemical compounds.

Front 44

Monatomic Ion

Back 44

an ion formed from a single atom.

Al³⁺

Front 45

Polyatomic Ion

Back 45

an ion consisting of two or more atoms chemically bonded together and carrying a net electric charge.

Metal + Nonmetal
SO₄²⁻

Front 46

Binary Molecular Compound

Back 46

a compound composed of only two elements.

Metal + Nonmetal
treated as Ionic

Nonmetal + nonmetal
Metalloid + Metalloid
Cl0₂ chlorine dioxide

Front 47

Acid

Back 47

a molecular compound that yields hydrogen ions, H⁺, and an anion for each acid molecule when dissolved in water.

Front 48

Oxoacid

Back 48

an acid containing hydrogen, oxygen and another element.

HNO₃
nitric acid

Front 49

Hydrate

Back 49

a compound that contains water molecules weakly bound in its crystals.

CuSO₄ · 5H₂O
copper(II) sulfate pentahydrate