Warm up week 21 2 of 4
Is this solid a crystal or polymer? How could
you tell?
Chapter Menu
Lesson 1: How Atoms Form Compounds
Lesson 2: Forming Solids
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5.1 How Atoms Form Compounds
compound
chemical formula
molecule
chemical bond
ionic bond
valence
covalent bond
Big Idea
1. Elements combine to form compounds
with new and different properties
2. Chemical bonds hold the atoms in
compounds together
Matter
Two types
Pure substance:
Has all same properties
Made of one thing: element or compound
Mixtures
5.1 How Atoms Form Compounds
Elements form Compounds
• A compound is a pure substance that
contains two or more elements.
• Compounds are chemical combinations of
elements with properties that are different
from the elements that formed them.
A chemical bond is a force that holds atoms
together in a compound.
Test Question!
When magnesium (Mg) metal is burned
in the presence of oxygen (O2 ),
magnesium oxide (MgO) is produced.
The properties of magnesium oxide
are different than the individual
properties of magnesium and oxygen
because magnesium oxide is ______
5.1 How Atoms Form Compounds
Chemical Formulas for Compounds
• A chemical formula contains element
symbols and subscripts to show the
elements and the number of atoms of
each element in the compound.
5.1 How Atoms Form Compounds
(cont.)
Describing Compounds
• The chemical formula for sucrose, C12H22O11,
includes all the atoms in one molecule.
Contrast an element and a compound
Which thinking map is that?
Ca F2
Which elements and how many of
each?
CuO
Which elements and how many of
each?
MgI2
Which elements and how many of
each?
AgNO3
Which elements and how many of
each?
Two Types of Compounds
Ionic Compounds & Covalent Compounds
• An ionic bond is an electrical attraction
between positively and negatively charged
ions in an ionic compound.
5.1 How Atoms Form Compounds
Ionic Bonds—Transferring Electrons
(cont.)
Properties of Ionic Compounds
• Metals bonded with nonmetals
• Usually solids at room temperature
• Brittle and break apart easily
• Have high melting and boiling points
• Many dissolve in water
5.1 How Atoms Form Compounds
Covalent Bonds—Sharing Electrons
• Some elements need to gain or lose too
many electrons.
• A covalent bond is a chemical bond
formed when atoms share electrons.
• A molecule is a neutral particle that forms
as a result of electron sharing.
5.1 How Atoms Form Compounds
Covalent Bonds—Sharing Electrons
(cont.)
5.1 How Atoms Form Compounds
Properties of Covalent Compounds
• Nonmetal bonded to nonmetal
• Can be solids, liquids, or gases at
room temperature
• Usually have lower melting and boiling
points than ionic compounds
• Do not usually separate in water
• Most do not conduct electricity
• Make living things
• Called molecules and can form polymers
5.1 How Atoms Form Compounds
Iron oxides, such as rust, form when iron
metal reacts with oxygen in the air. What
are the chemical symbols for the two
elements found in iron oxide?
A I and O
B Ir and O
C Fe and O
D Pb and O
5.1 How Atoms Form Compounds
Covalent bonds usually form
between
A nonmetal and metal
B noble gas and nonmetal
C nonmetal and nonmetal
D atoms and noble gasses
5.1 How Atoms Form Compounds
Ionic or Covalent?
1. MgO
2. CO2
C HCl
D NaCl
5.2 Forming Solids
metal
crystal
metallic bond
unit cell
malleability
polymer
ductility
monomer
Big Idea 5.2 Notes
1. Solids are formed generally in two ways;
crystals and polymers
2. Anything can form crystal
3. Polymers are huge covalent compounds
Crystals
5.2 Forming Solids
• A crystal is a regular, repeating
arrangement of atoms, ions, or molecules.
• Crystals are formed from repeating
patterns.
Ionic compounds always form crystals
Using a crystal lattice of positive and
negative ions
1. What is the
repeating pattern?
2. Is this an ionic or
covalent
compound?
SALT CRYSTAL
• http://www.brainpop.com/science/earthsyst
em/crystals/
World’s largest crystals (gypsum)
5.2 Forming Solids
Metal Atoms and Crystals
• Metal atoms combine in a regular pattern
(crystal) in which some electrons are free
to move about.
5.2 Forming Solids
Metallic Bonds & Crystals
• A metallic bond is formed when many
metal atoms share their pooled electrons.
• Metal atoms can bond to
atoms of the same element,
or to other metals.
5.2 Forming Solids
Bonding and Properties
• Metals are good conductors because their
electrons move freely.
• Metals can be hammered into sheets
(malleable) or pulled into wires (ductile)
without breaking.
5.2 Forming Solids
What is a polymer?
• A polymer is a covalent compound made
up of many repeating units linked together
in a chain.
• A monomer is a single molecule that
forms a link in a polymer chain.
• Many hundreds of monomers link together
to form a solid polymer.
Synthetic Polymers
5.2 Forming Solids
• Synthetic polymers, such as polyethylene,
are polymers manufactured by humans.
5.2 Forming Solids
Natural Polymers
• All living cells must have three kinds of
natural organic polymers—proteins,
carbohydrates, and nucleic acids.
5.2 Forming Solids
Natural Polymers
(cont.)
• Amino acid monomers join together to form
a protein.
• Protein and carbohydrate polymers shown
with their monomers.
5.2 Forming Solids
What holds carbohydrates together?
A ionic bonds
B metallic bonds
C covalent bonds
D electron clouds
5.2 Forming Solids
Which of the following is the
most malleable?
A crystal
B polymer
C metal
D monomer
5.2 Forming Solids
A(n) ____ is the smallest repeating
pattern in a crystal.
A monomer
B polymer
C metallic bond
D unit cell
Chapter Resources Menu
Chapter Assessment
California Standards Practice
Concepts in Motion
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How many dots are in a Lewis dot
diagram for the Group 1 element
lithium?
A 1
B 2
C 3
D 4
Which is an example of a natural
polymer?
A sodium chloride
B polyethylene
C polysaccharide
D quartz
Why are noble gases unlikely to form
compounds with other elements?
A They form ionic bonds.
B They have 8 valence electrons.
C They form covalent bonds.
D Their outer energy levels are not filled
with electrons.
Compounds sharing electrons are
held together by ____.
A ionic bonds
B covalent bonds
C metallic bonds
D polymer chains
A polymer is made up of many
repeating monomers held
together by ____.
A metallic bonds
B polymer chains
C ionic bonds
D covalent bonds
SCI 3.b
Which elements are least likely to
react with other elements?
A metals
B Group 17 elements
C Group 16 elements
D Noble gases
SCI 3.b
In the ionic compound magnesium
oxide (MgO), how many electrons
did oxygen give magnesium?
A 1
B 2
C 3
D none of the above
SCI 3.c
Metals are good conductors
because ____.
A their electrons move freely
B their protons move freely
C they have ionic bonds
D none of the above
SCI 3.f
Noble gases are in which group on
the periodic table?
A 1
B 2
C 17
D 18
SCI 7.c
Which property of copper allows it to
be pulled into wires?
A ductility
B malleability
C conductivity
D luster
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