Dalton's Atomic Theory

All matter is composed of ultimately small particles, called atoms.
Atoms are permanent and indivisible - they can neither be created nor destroyed.
Elements are characterized by their atoms. All atoms of a given element are identical in all respects. Atoms of different elements have different properties.
Chemical change consists of a combination, separation, or rearrangement of atoms.
Chemical compounds are composed of atoms of two or more elements in fixed ratios.

Writing Formulae and Naming Compounds

Note that formulae are generally written with the elements ordered by electronegativity (roughly, elements on the left side of the Periodic table precede those on the right).

You should know about the Stock system of nomenclature for cations and ionic compounds.

For cations with a single oxidation state (Type I) the name of the element is the name of the cation (no Roman numeral is necessary)

For cations with more than one oxidation state or charge (Type II) the oxidation number of a cation is indicated by Roman numerals in parenthesis following the symbol with no space, e.g. Fe(III), and the name is then the element name plus the number Fe(III) = iron three = iron(III).

The Nuclear Atom

Particle	Charge	Relative Mass	Mass
Electron (e^-)	-1	1/1840	9.11 x 10^-28g
Proton (p or H⁺)	+1	ª1	1.67 x 10^-24g
Neutron (n)	0	ª1	1.67 x 10^-24g

Some important terms which you must know are:

Atomic number (Z) - the number of protons in the nucleus. This number is characteristic of a given element.
Atomic mass number (A) - the sum of the protons and neutrons in a given atom (p + n).
Atomic mass - the actual mass of an average atom in a sample. The characteristic atomic masses for Earth are shown on periodic tables.
Atomic Mass Unit: the atomic mass unit = amu is a unit of mass for atoms. It is defined as 1/12 the mass of one atom of ¹²C, where the mass of ¹²C is defined as 12 exactly.

Symbol Z A p n e^-

¹⁴C

²³⁸U⁶⁺

³⁵Cl^-

¹⁸O^2-

**Periodic Table of the Elements**
IA	IIA											IIIA	IVA	VA	VIA	VIIA	VIIIA
H																	He
Li	Be											B	C	N	O	F	Ne
Na	Mg	IIIB	IVB	VB	VI	VIIB	VIIIB			IB	IIB	Al	Si	P	S	Cl	Ar
K	Ca		Ti	V	Cr	Mn	Fe	Co	Ni	Cu	Zn	Ga	Ge	As	Se	Br	Kr
Rb	Sr									Ag	Cd		Sn			I	Xe
Cs	Ba				W				Pt	Au	Hg		Pb

© R A Paselk

Last modified30 Janaury 2009

Dalton's Atomic Theory

All matter is composed of ultimately small particles, called atoms.

Atoms are permanent and indivisible - they can neither be created nor destroyed.

Elements are characterized by their atoms. All atoms of a given element are identical in all respects. Atoms of different elements have different properties.

Chemical change consists of a combination, separation, or rearrangement of atoms.

Chemical compounds are composed of atoms of two or more elements in fixed ratios.

Writing Formulae and Naming Compounds

Note that formulae are generally written with the elements ordered by electronegativity (roughly, elements on the left side of the Periodic table precede those on the right).

You should know about the Stock system of nomenclature for cations and ionic compounds.

For cations with a single oxidation state (Type I) the name of the element is the name of the cation (no Roman numeral is necessary)

For cations with more than one oxidation state or charge (Type II) the oxidation number of a cation is indicated by Roman numerals in parenthesis following the symbol with no space, e.g. Fe(III), and the name is then the element name plus the number Fe(III) = iron three = iron(III).

The Nuclear Atom

The Nuclear Atom

Particle

Charge

Relative Mass

Mass

Some important terms which you must know are:

Atomic number (Z) - the number of protons in the nucleus. This number is characteristic of a given element.

Atomic mass number (A) - the sum of the protons and neutrons in a given atom (p + n).

Atomic mass - the actual mass of an average atom in a sample. The characteristic atomic masses for Earth are shown on periodic tables.

Atomic Mass Unit: the atomic mass unit = amu is a unit of mass for atoms. It is defined as 1/12 the mass of one atom of ¹²C, where the mass of ¹²C is defined as 12 exactly.

Dalton's Atomic Theory

All matter is composed of ultimately small particles, called atoms.

Atoms are permanent and indivisible - they can neither be created nor destroyed.

Elements are characterized by their atoms. All atoms of a given element are identical in all respects. Atoms of different elements have different properties.

Chemical change consists of a combination, separation, or rearrangement of atoms.

Chemical compounds are composed of atoms of two or more elements in fixed ratios.

Writing Formulae and Naming Compounds

Note that formulae are generally written with the elements ordered by electronegativity (roughly, elements on the left side of the Periodic table precede those on the right).

You should know about the Stock system of nomenclature for cations and ionic compounds.

For cations with a single oxidation state (Type I) the name of the element is the name of the cation (no Roman numeral is necessary)

For cations with more than one oxidation state or charge (Type II) the oxidation number of a cation is indicated by Roman numerals in parenthesis following the symbol with no space, e.g. Fe(III), and the name is then the element name plus the number Fe(III) = iron three = iron(III).

The Nuclear Atom

The Nuclear Atom

Particle

Charge

Relative Mass

Mass

Some important terms which you must know are:

Atomic number (Z) - the number of protons in the nucleus. This number is characteristic of a given element.

Atomic mass number (A) - the sum of the protons and neutrons in a given atom (p + n).

Atomic mass - the actual mass of an average atom in a sample. The characteristic atomic masses for Earth are shown on periodic tables.

Atomic Mass Unit: the atomic mass unit = amu is a unit of mass for atoms. It is defined as 1/12 the mass of one atom of 12C, where the mass of 12C is defined as 12 exactly.

Atomic Mass Unit: the atomic mass unit = amu is a unit of mass for atoms. It is defined as 1/12 the mass of one atom of ¹²C, where the mass of ¹²C is defined as 12 exactly.