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Classification of MatterChapter 3
Hein and Arena
Eugene Passer
Chemistry Department
Bronx Community College
© John Wiley and Sons, Inc
Eugene Passer
Chemistry Department
Bronx Community College
© John Wiley and Sons, Inc
Version 1.0
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Matter Defined
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Matter is anything that has mass
and occupies space. It can be pure
or a mixture.
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Physical States of
Matter
(Solid, Liquid and Gas)
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Definite shape
Definite volume
Particles are close
Very slight compressibility
SOLIDS
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Solid
Amorphous Solid Crystalline Solid
Particles lack a regular
internal arrangement
Particles exist in regular, repeating
three-dimensional geometric patterns.
Glass, plastics, gels Diamond, metals, salts
A solid can be either crystalline or amorphous
depending on the internal arrangement of the particles
that constitute the solid.
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Indefinite shape
Definite volume
Particles are close – not as close as in solids
Slight compressibility – greater than solids
LIQUIDS
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GASES
No fixed shape
No fixed volume
Particles are far apart
Very compressible
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ATTRACTIVE FORCES
Solid particles have strong attractive
forces between them (i.e. “closest” proximity).
Liquid particles have intermediate attractive
forces between them (i.e. “medium” proximity).
Gas particles have extremely weak attractive
forces between them (i.e. “least” proximity).
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Substances and
Mixtures
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Substance
A particular kind of matter that has a fixed
composition and distinct properties.
Examples
ammonia, water, and oxygen.
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Homogeneous Matter
Matter that is uniform in appearance
and properties throughout.
Examples
Ice (without bubbles) , milk, pure gold
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Heterogeneous Matter
Matter that is not uniform in appearance
or properties throughout.
Examples
ice and water, wood
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Homogeneous
Heterogeneous
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The Three Phases of Matter
Solid phaseLiquid phaseGas phase
Examples
In an ice water mixture, ice is the solid
phase and water is the liquid phase.
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Mixture
Matter containing 1, 2 or more substances that can be homogeneous or heterogeneous.
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Homogeneous Mixture (Solutions)
A homogeneous mixture consists of 2 or
more substances, and has one phase (i.e.
solid, liquid or gas).
Example
Sugar completely dissolved in water.
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Example
Sand added to water.
Heterogeneous Mixture
A heterogeneous mixture consists of 2 or
more phases of one or more substances.
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Heterogeneous Mixture
of One Substance
A pure substance can exist as different
phases in a heterogeneous system.
Example
Ice floating in water.
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Elements
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An element is a fundamental substance
that cannot be broken down into simpler
substances by simple chemical or
physical means.
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Each element has a number; the atomic number.
Hydrogen has an atomic number of 1.
Calcium has an atomic number of 20.
Iron has an atomic number 26.
The atomic number defines what the element.
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ATOM
• The atom is the smallest particle of an
element that exhibits the characteristic
properties of the element.
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Symbols of the
Elements
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• A symbol of an element stands for …
– the element itself
– one atom of the element
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Ne neon
Rules governing symbols of the elements
are:
1. Symbols have either one or two letters.
2. If one letter is used, it is
capitalized.
3. If two letters are used, only
the first is capitalized.
H hydrogenC carbon
Ba barium
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Today’s Assignment!
• Please learn the names and chemical
symbols of elements 1 through 36 and
82. Thanks!
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Metals, Nonmetals
and Metalloids
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Metals
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• Have relatively high melting points
• Have high densities (g/mL).
• Excellent conductors of heat and electricity
• At room temperature metals are solids except
mercury.
Physical Properties of metals
• High luster
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• Many metals readily combine with nonmetalsto form compounds called ionic compounds.
– They can combine with sulfur.
• Metals have little tendency to combine with
each other to form compounds.
chlorine.
Chemical Properties of Metals
oxygen.
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Nonmetals
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• Have relatively low melting points
• Have low densities.
• Poor conductors of heat and electricity
• At room temperature carbon, phosphorous
and sulfur are solids.
Physical Properties of Nonmetals
• Lack luster
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• Many nonmetals readily combine with othernonmetals to form compounds calledmolecular compounds.
Chemical Properties of Nonmetals
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Metalloids
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Metalloids have properties that
are intermediate between metals
and nonmetals
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The Metalloids
1. boron
2. silicon
3. germanium
4. arsenic
5. antimony
6. tellurium
7. polonium
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Metals are found to the left of the metalloidsNonmetals are found to the right of the metalloids.
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Compounds
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A compound is a distinct substance that
contains two or more atoms combined in
a definite proportion.
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• Compounds can be decomposed into
simpler substances.
• Elements cannot be easily decomposed
into simpler substances.
• Atoms of a compound are always
present in whole numbers.
CH4, C2H4, AlCl3, etc.
The subscripts in the formula represents the
number of atoms of each element present.
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Ba3(PO4)2
indicates three
Ba atoms
3-
4phosphate (PO )
indicates two
groups
indicates
the element
barium
indicates the phosphate group
composed of one phosphorous
atom and four oxygen atoms
Channel Setting Instructions for ResponseCard RF
1. Press and release the "GO" or "CH" button.
2. While the light is flashing red and green, enter the 2 digit channel code (i.e. channel 1 = 01, channel 21 = 21).
Channel is 02
3. After the second digit is entered, Press and release the "GO" or "CH" button. The light should flash green to confirm.
4. Press and release the "1/A" button. The light should flash amber to confirm.
How many atoms are present in Li2SO4?
1 2 3 4
28%
3%
68%
2%
1. 6
2. 4
3. 7
4. 3
How many atoms are present in Li2SO4?
There are 2 lithium (Li) atoms, 1 sulfur (S) atom and 4 oxygen (O) atoms for a total of seven atoms.
The subscripts represent the number of atoms of each element present in the formula.
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There are two types of compounds:
molecular and ionic.
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Molecules
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A molecule is an individual unit of a
compound formed by the combination
(i.e. bonding) of two or more atoms,
typically nonmetals atoms.
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• A water molecule consists of two
hydrogen atoms and one oxygen atom.
3.5
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Ionic Compounds
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Ionic compounds are held together by
electrostatic attractive forces between
positively and negatively charged ions.
Ionic compounds result when the ions of a
metal and a nonmetal combine
An ion is a positively or negatively charged
atom (monatomic ion) or group of
atoms (polyatomic ion).
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A positively charged ion is called a
Cation; typically a metal.
Na Na+ + e-
3.5
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A negatively charged ion is called an
Anion; typically a nonmetal.
Cl + e- Cl-
3.5
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Positively charged sodium ions and
negatively charged chloride ions.
Sodium Chloride
3.5
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The crystalline structure of sodium chloride.
Sodium Chloride
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Ionic Compound Formulas
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Sodium chloride and other ionic
compounds consist of large aggregates
of cations and anions.
The formulas of ionic compounds are
expressed as the smallest whole number
ratio that exists between the cations and
the anions.
NaClCaCl2
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• The formula NaCl does not mean that
a molecule of NaCl exists; it does not!
• The formula NaCl means that the
ratio of sodium to chlorine in a
sodium chloride crystal is 1:1.
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The ratio of Na+ to Cl- is 1:1
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3.4
Compounds can be classified as molecular or
ionic.
Ionic compounds – ionic bonds.
Molecular compounds - covalent bonds.
Nonmetal - Nonmetal Metal - Nonmetal
Ionic Bonds: a complete transfer of e- from metal to nonmetal.
Covalent Bonds: a sharing of e- between the nonmetal and
nonmetal.
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Elements That Exist as
Diatomic Molecules
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A diatomic molecule contains exactly two
atoms of the same element.
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Chemical Formulas
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Rules for Writing Chemical Formulas
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NaCl
indicates
the element sodium
(one atom); the metal
appears 1st in formula.
indicates
the element chlorine
(one atom); the non-
metal appears 2nd in
Formula.
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indicates
3 H atoms
indicates
the element
phosphorous (P)
indicates
the element
hydrogen (H)
indicates
the element
oxygen (O)H3PO4
indicates
4 O atoms
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When a formula contains two or more ofthe same polyatomic ion, parentheses areplaced around it, and the number of unitsof the group is indicated by a subscriptplaced to the right of the parentheses.
Phosphate ion: PO4-3
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Ba3(PO4)2
indicates three
Ba atoms
3-
4phosphate (PO )
indicates two
groups
indicates
the element
barium
indicates the phosphate group
composed of one phosphorous
atom and four oxygen atoms
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Formulas written as H2O, H2SO4,
Ca(NO3)2 and C6H6 do not show the
spatial arrangements of the atoms.
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H2O
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