Classification of Matter Chapter 3 Larry Emme Chemeketa Community College

Matter Defined

Matter is anything that has mass and occupies space. Matter can be invisible. Matter appears to be continuous and unbroken.

Physical States of Matter

Physical Properties of Solids, Liquids, and Gases State Shape Volume Particles Compressibility Solid Definite Tightly packed Very Slight Liquid Indefinite Mobile; Cohering Slight Gas Independent High

Substances and Mixtures

Matter refers to all of the materials that make up the universe.

Substance A particular kind of matter that has a fixed composition and distinct properties. Examples ammonia, water, and oxygen. NH3 H2O O2

Homogeneous Matter Examples Matter that is uniform in appearance and with uniform properties throughout. Examples ice, soda, solid gold

Heterogeneous Matter Examples Matter with two or more physically distinct phases present. Examples wood, blood

Phase A homogenous part of a system separated from other parts by physical boundaries. Examples In an ice water mixture ice is the solid phase and water is the liquid phase

Mixture Matter containing 2 or more substances that are present in variable amounts. Mixtures are variable in composition. They can be homogeneous or heterogeneous.

Homogeneous Mixture (Solution) A homogeneous mixture of 2 or more substances. It has one phase. Example Sugar and water. Before the sugar and water are mixed each is a separate phase. After mixing the sugar is evenly dispersed throughout the volume of the water.

Heterogeneous Mixture A heterogeneous mixture consists of 2 or more phases. Example Sugar and fine white sand. The amount of sugar relative to sand can be varied. The sugar and sand each retain their own properties.

Classification of matter: A pure substance is always homogeneous in composition, whereas a mixture always contains two or more substances and may be either homogeneous or heterogeneous.

Learning Check Freshly opened Coke is an example of a An element A compound A homogeneous mixture A heterogeneous mixture

Learning Check Freshly opened Coke is an example of a An element A compound A homogeneous mixture A heterogeneous mixture

Comparison of Mixtures and Compounds Composition May be composed of elements, compounds, or both in variable composition Composed of two or more elements in a definite, fixed proportion by mass Separation By physical or mechanical means Only by chemical changes Identification Components do not lose their identity A compound does not resemble the elements from which it is formed

Learning Check A clear, colorless liquid is heated in a beaker until all of the liquid is gone. The walls of the beaker are coated with a white crystalline solid. The liquid was: An element A compound A homogeneous mixture A heterogeneous mixture

Learning Check A clear, colorless liquid is heated in a beaker until all of the liquid is gone. The walls of the beaker are coated with a white crystalline solid. The liquid was: An element A compound A homogeneous mixture A heterogeneous mixture

Elements

An element is a fundamental or elementary substance that cannot be broken down into simpler substances by chemical means

Each element has a number. All known substances on Earth and probably the universe are formed by combinations of more than 100 elements. Each element has a number. Beginning with hydrogen as 1 the elements are numbered in order of increasing complexity.

Most substances can be decomposed into two or more simpler substances. Water can be decomposed into hydrogen and oxygen. Table salt can be decomposed into sodium and chlorine. An element cannot be decomposed into a simpler substance.

ATOM The smallest particle of an element that can exist. The smallest unit of an element that can enter into a chemical reaction.

Distribution of Elements

Elements are not distributed equally by nature. Oxygen is the most abundant element in the human body (65%). Oxygen is the most abundant element in the crust of the earth (49.2%). In the universe the most abundant element is hydrogen (91%) and the second most abundant element is helium (8.75%).

Distribution of the common elements in nature.

Names of the Elements

Sources of Element Names Greek-Color Iodine: from the Greek iodes meaning violet. Latin- Property Fluorine: from the Latin fluere meaning to flow. German- Color Bismuth: from the German weisse mass meaning white mass. Location Germanium: discovered in 1866 by a German chemist. Famous- Scientist Einsteinium: named for Albert Einstein.

Sources of Element Names Famous- Warrior Xenon: named for Xena the warrior princess. Famous- Scientist Rutherfordium: named for Ernest Rutherford. Location Californium: discovered in 1950 at the Univ. of California at Berkeley.

Symbols of the Elements

A symbol stands for the element itself one atom of the element a particular quantity of the element

Rules governing symbols of the elements are: Symbols have either one or two letters. If one letter is used it is capitalized. C carbon H hydrogen If two letters are used, only the first is capitalized. Ba barium Ne neon

50 Common Elements and Their Symbols Al aluminum Cr chromium Li lithium Rn radon Sb antimony Co cobalt Mg magnesium Rb rubidium Ar argon Cu copper Mn manganese Se selenium As arsenic F fluorine Hg mercury Si silicon Ba barium Ga gallium Ne neon Ag silver Be beryllium Ge germanium Ni nickel Na sodium B boron Au gold N nitrogen Sr strontium Br bromine He helium O oxygen S sulfur Ca calcium H hydrogen P phosphorus Sn tin C carbon I iodine Pt platinum W tungsten Cs cesium Fe iron K potassium U uranium Cl chlorine Kr krypton Ra radium Xe xenon Pb lead Zn zinc

Metals, Nonmetals and Metalloids

Metals

Most elements are metals Metals are solid at room temperature. Mercury is an exception. At room temperature it is a liquid. Metals are good conductors of heat and electricity. Most elements are metals physical properties of metals Metals are malleable (they can be rolled or hammered into sheets). Metals have high luster (they are shiny).

Metals have high densities Metals are ductile (they can be drawn into wires). Most metals have a high melting point. Metals have high densities

Nonmetals

Physical Properties of Nonmetals Lack luster (they are dull) Have relatively low melting points Have low densities. Poor conductors of heat and electricity At room temperature carbon, phosphorous, sulfur, selenium, and iodine are solids.

Metalloids

Metalloids have properties that are intermediate between metals and nonmetals

The Metalloids boron silicon germanium arsenic antimony tellurium polonium

Metals are found to the left of the metalloids Nonmetals are found to the right of the metalloids Metals 1 H 2 He 3 Li 4 Be 5 B 6 C 7 N 8 O 9 F 10 Ne 11 Na 12 Mg 13 Al 14 Si 15 P 16 S 17 Cl 18 Ar 19 K 20 Ca 21 Sc 22 Ti 23 V 24 Cr 25 Mn 26 Fe 27 Co 28 Ni 29 Cu 30 Zn 31 Ga 32 Ge 33 As 34 Se 35 Br 36 Kr 37 Rb 38 Sr 39 Y 40 Zr 41 Nb 42 Mo 43 Tc 44 Ru 45 Rh 46 Pd 47 Ag 48 Cd 49 In 50 Sn 51 Sb 52 Te 53 I 54 Xe 55 Cs 56 Ba 57 La 72 Hf 73 Ta 74 W 75 Re 76 Os 77 Ir 78 Pt 79 Au 80 Hg 81 Tl 82 Pb 83 Bi 84 Po 85 At 86 Rn 87 Fr 88 Ra 89 Ac 104 Rf 105 Db 106 Sg 107 Bh 108 Hs 109 Mt 110 Ds 111 Rg 112 Cn 113 Nh 114 Fl 115 Mc 116 Lv 117 Ts 118 Og Metalloids Nonmetals 58 Ce 59 Pr 60 Nd 61 Pm 62 Sm 63 Eu 64 Gd 65 Tb 66 Dy 67 Ho 68 Er 69 Tm 70 Yb 71 Lu 90 Th 91 Pa 92 U 93 Np 94 Pu 95 Am 96 Cm 97 Bk 98 Cf 99 Es 100 Fm 101 Md 102 No 103 Lr

Compounds

A compound is a distinct substance that contains two or more elements combined in a definite proportion by weight.

There are two types of compounds: molecular and ionic.

Molecules

A molecule is the smallest uncharged individual unit of a compound formed by the union of two or more atoms.

A water molecule consists of two hydrogen atoms and one oxygen atom. If it is subdivided the water molecule will be destroyed and hydrogen and oxygen will be formed.

Ionic Compounds

An ion is a positively or negatively charged atom or group of atoms.

A cation is a positively charged ion.

Thanks to Claire de Noyo Fall 2015

An anion is a negatively charged ion.

Ionic compounds are held together by attractive forces between positively and negatively charged ions.

Thanks to Elizabeth Gimzewski (Fall 2011)

Ionic Compound Formulas

Sodium chloride and other ionic compounds consist of large aggregates of cations and anions.

The actual chemical formulas of ionic compounds express the smallest whole number ratio that exists between these cations and the anions.

The formula NaCl does not mean that a molecule of NaCl exists. The formula NaCl means that the ratio of sodium to chlorine in a sodium chloride crystal is one to one.

The ratio of Na+ to Cl- is 1:1

Compounds can be classified as molecular or ionic Compounds can be classified as molecular or ionic. Ionic compounds are held together by attractive forces between their positive and negative charges. Molecular compounds are held together by covalent bonds.

Elements That Exist as Diatomic Molecules

A diatomic molecule contains exactly two atoms of the same or different elements.

Elements That Exist as Diatomic Molecules Symbol Molecular Formula Hydrogen H H2 Nitrogen N N2 Oxygen O O2 Fluorine F F2 Chlorine Cl Cl2 Bromine Br Br2 Iodine I I2

Chemical Formulas

Ca calcium CaCl2 Cl chlorine chemical formulas Show the symbols of the atoms of the elements present in a compound. CaCl2 Ca calcium Cl chlorine

CaCl2 chemical formulas Show the ratio of the atoms of the elements present in a compound. CaCl2

Rules for Writing Chemical Formulas

When a formula contains one atom of an element the symbol of that element represents the one atom. The number one (1) is not used as a subscript.

NaCl indicates the element sodium (one atom) indicates the element chlorine (one atom)

When the formula contains more than one atoms of an element the number of atoms is indicated by a subscript written to the right of the symbol of that atom.

H3PO4 indicates the element oxygen (O) indicates indicates the element hydrogen (H) indicates the element phosphorous (P) indicates 4 O atoms indicates 3 H atoms

When the formula contains more than one of a group of atoms that occurs as a unit, parentheses are placed around the group, and the number of units of the group is indicated by a subscript placed to the right of the parentheses.

Ba3(PO4)2 indicates the element barium indicates three Ba atoms indicates the phosphate group composed of one phosphorous atom and four oxygen atoms indicates three Ba atoms

Formulas written as H2O, H2SO4, Ca(NO3)2 and C12H22O11 show only the number and kind of each atom contained in the compound; they do not show the arrangements of the atoms in the compound or how they are chemically bonded to each other.

The End