Chapter 1: Atomic
Structure and the
Periodic Table
Section 1.1: Atoms are the
smallest form of elements
All matter is made of atoms
 Are all substances we touch the same?
– Example: A book is made of a different _________
then air.
 First it was thought everything was made of:
– Air, ______, fire, and earth
 Today chemists know about ____ basic
substances, or _________, account for
everything we see or touch.
 Element is related to the word “elementary”
which means “______”
Types of Atoms in Earth’s
Crust and Living Things
EARTH'S CRUST
Other
12%
Aluminum
8%
Iron
5%
Silicon
28%
Oxygen
47%
Types of Atoms in Earth’s
Crust and Living Things
HUMANS
Other
3%
Nitrogen
3%
Hydrogen
10%
Carbon
23%
Oxygen
61%
Names and Symbols of Elements
 Where do these names come from?
– People, ______, and Greek words
 Symbols
– First Letter of Its Name
 Hydrogen ___
 Sulfur ___
 Carbon ___
– First Letter Plus One More Letter
 Aluminum ____
 Platinum ____
 Zinc ____
Names and Symbols of Elements
(cont.)
 Some symbol names are less obvious.
– Symbols from Latin Name
 Gold ____
 Lead ____
 Iron ____
 Copper ____
Each Element is Made of
Different Atoms
 Dalton was the first to propose that each
________ is made of tiny particles called
______.
 Atoms are made of even smaller particles
– ________
– ________
– ________
The Atomic Model
__________
________
___________
_______________
The Structure of an Atom
 Proton
– A __________ charged particle located in an atom’s nucleus.
 Neutron
– A particle that has __________ charge and is located in an atom’s nucleus.
 Nucleus
– The central region of an atom where most of the atom’s mass is found in
________________.
**THE ___________ HAS AN OVERALL POSITIVE CHARGE**
The Structure of an Atom
 Electron
– A ___________ charged particle located outside an
atom’s nucleus.
– An electron is about ______ times smaller than either a
proton or neutron.
**The ______________ has a negative charge**
 Neutral atoms have no electrical charge because
they have the ______ number of _______ as
_________.
Atomic Number
 The number of _______ in the nucleus of an
atom.
 This determines the ______ of an atom.
 Ex. Every hydrogen atom has an
_______________ of 1, it has exactly one
proton in its nucleus.
Atomic Mass Number
 The total number of _______ and ________
in an atom’s nucleus.
 Atoms of a certain element always have the
same number of ______, but may not
always have the same number of ________.
 So, not all atoms of an ________ have the
same atomic mass number.
 What are these atoms called????
Isotopes
 Atoms of the same element that have a
_________ number of ________.
 Ex. All chlorine atoms have 17 protons.
However, some chlorine atoms have 18
neutrons, while other chlorine atoms have
20 neutrons.
 Some elements have many ________, while
others just have a ____.
Atoms Form Ions
 An ____ is formed when an atom ______ or
______ one or more ________.
 The number of ________ in an ion is
_________ from the number of ________.
 An ion ____ have an overall electric charge.
Formation of a Positive Ion
 A ______ ion is formed when an atom
______ an electron.
 A positive ion is ______ than the atom that
formed it because it has ______ electrons.
 Positive ions are represented by the symbol
for the element with a raised ____ sign to
indicate a positive _______.
– Ex.
Formation of a Negative Ion
 A _______ ion is formed when an atom
______ an electron.
 A negative ion is ______ than the atom that
formed it because it has _____ electrons.
 Negative ions are represented by the
symbol for the element with a raised _____
sign to indicate a ________ charge.
– Ex.