Transcript Chapter 3: The Structure of Matter

Chapter 2:
Minerals and
Their Properties
2-1:
What are Elements
& compounds?
•Atom building block of
matter; smallest part of
an element
•Elements  matter that
has only one kind of
atom
•All atoms of an element
are exactly alike
•Each element has unique
properties
•There are more than 118
known elements; 92 are
natural elements
•A natural element is one
that is found in nature
•Compound  2 or more
elements chemically
combined
•Molecule  smallest particle
of a substance that has the
same properties of the
substance
•The properties of a
compound are usually
different from the
elements that make it
•Example: Liquid water is
made up of hydrogen gas
and oxygen gas
•Table salt is made up of
sodium (a solid) and
chlorine (a poisonous
gas)
•There are more than 10
million known
compounds
•Molecule  smallest part
of a compound
•Each water molecule has
3 atoms- 2 small atoms
and 1 larger atom
•The center part of an
atom is called the
nucleus
•The nucleus contains
protons and neutrons
•Protons  positively
charged symbol is a plus
(+) sign labeled with a p
• Neutrons  neutral
symbol is 0 labeled with an
n
•Electrons  particles in an
atom that move around
the nucleus
•Electrons  negatively
charged symbol is a
minus (-) sign labeled
with an e
•The number of
protons an atoms has
equals the number of
electrons
•Atomic Number =
Number of protons =
Number of electrons
•Mass Number tells
how heavy the
nucleus is
•Mass Number =
Number of Protons +
Number of Neutrons
•Number of Neutrons
= Mass Number –
Number of Protons
•Number of Protons =
Mass Number –
Number of Neutrons.
•Number of Protons =
Number of Electrons.
electron
neutron
proton
Energy Levels, Orbitals, &
Electrons
Energy Level
1
Number of
Orbitals
1
Max. Number
of Electrons
2
2
4
8
3
9
18
4
16
32
Bohr Models
• Bohr models shows the total
number of electrons in an
element.
Lewis Structures AKA
Electron Dot Diagrams
•Valence electrons 
electrons in the outer
energy level
•Electron dot diagrams (EDD)
 just the valence
electrons
Lewis Structures:
Electron Dot Diagrams
2-2: What are Chemical
Formulas?
Element Symbols
•All symbols have one,
two, or three letters
•The first letter is always
capitalized
•The second and third
letters are lowercase
•Even though it is an
abbreviation, there is no
period at the end
•Just the first letter of their
name
•The first two letters of
their name
•Three letter of their name
•Some symbols are based
on their Latin names
•Chemical Formula 
shows the elements
that make up a
compound & its
subscript tells how
many of each element
Periodic Table
•Mendeleev was the first
to arrange the elements;
he arranged them by
mass
•Elements are on the
modern periodic table
are arranged by
atomic number
(number of protons)
•Each square of the
periodic table includes
atomic number
symbol
element name
mass number
•Isotopes are forms of the
same element; they have
the same atomic number
(same number of protons),
but they have different
number of neutrons; so
they have different mass
numbers
•Columns in the periodic
table are called groups or
families
•Rows in the periodic table
are called periods
•There are 18
groups/families and 7
periods on the period
table.
Types of Compounds
•Ionic compounds  formed
when a metal and
nonmetal bond
•Covalent Compounds form
when a nonmetal and
nonmetal bond
2-3: What are Minerals?
•75% of the crust is
made of oxygen and
silicon
•Silica  silicon + oxygen
4 Criteria to be a mineral
•Mineral 
–Inorganic  never living
–Naturally occurring  not
man-made
–Definite chemical makeup
–Crystal structure
2-4, 2-5, & 2-6:
Identifying minerals
•Physical properties
–Color
–Streak  color of the
powder
–Luster 
metallic/nonmetallic
–Hardness  Mohs scale
–Texture
–Cleavage  split smoothly
–Fracture  break into uneven
pieces
–Crystalline structure
–Magnetism
–Acid test  does it fizz
in HCl = contains CaCO3