Chemistry And Hazards Of Hazardous Materials And Weapons .

Chemistry and Hazards of Hazardous Materialsand Weapons of Mass DestructionChapter ContentsCase History.145Atoms.146Periodic Table of Elements.146Four Significant Families.147Group I – The Alkali Metals.153Group II – The Alkaline Earths.154Group VII – The Halogens.155Group VIII – The Noble es.162Bonding.164The Octet/Duet Rule.165Stability of Elements and Compounds.166Diatomic Molecules (Compounds).166Ionic Bonds.166Covalent Bonds.168Resonant Bonds.168Bond Energy.169Bonding in Haz Mat sition.174Synergistic Reactions.174The Fundamentals of a Reaction.175Common Families of HazardousMaterials.176Inorganic Compounds.176Organic Compounds.176Oxidizers.180Reactive Materials.181Corrosives.185Special Hazards of Chemicals and Weaponsof Mass Destruction.186Chemical Warfare Agents.186Biological Agents and Toxins.190Explosives and Incendiaries.192Pesticides and Agricultural .195Chapter Summary.198Review Questions.198Exothermic and Endothermic Reactions.171Oxidation and Combustion.171142Chapter 4 Chemistry and Hazards of Hazardous Materials and Weapons of Mass Destruction

4Key TermsActivation Energy. 175Air-Reactive Material.182Anions.167Atom.146Binary Salt.161Bond ent Bond.168Deflagration.193Detonation.193Diatomic Molecule.158Dissociation.185Electron.146Element. 147Explosive.192Half-Life.196Inert Gas.156Inhibitor. 174Inorganic Peroxide. 181Ion.167Ionic .146Nucleus.146Organic Peroxide. zation.173Proton.146Reactive Material. 171Resonant tive Material.182NFPA CompetenciesNFPA 472 References7.2.1.47.2.2.2(2, 4, 5, 7-10, 13, 20, 23-27, 30, 31, 33, 36-37, 40-42, 44, 52)Chapter 4 Chemistry and Hazards of Hazardous Materials and Weapons of Mass Destruction143

Chemistry and Hazards of Hazardous Materialsand Weapons of Mass DestructionLearning Objectives1.Define atoms.2.Describe the basic arrangement of the periodic table of elements.3.Explain the four significant families of elements.4.Describe matter. [NFPA 472, 7.2.2.2(10, 36, 44)]5.Explain the concept of bonding. [NFPA 472, 7.2.2.2(24, 25)]6.Explain the various types of reactions. [NFPA 472, 7.2.2.2(7-8, 23, 37)]7.Describe common families of hazardous materials. [NFPA 472, 7.2.2.2(2, 4, 9, 13, 27, 31, 41, 42)]8.Identify special hazards of chemicals and weapons of mass destruction. [NFPA 472, 7.2.2.2 (4, 5,26, 30, 33, 40, 52)]9.Discuss radiation. [NFPA 472, 7.2.1.4, 7.2.2.2(20)]144Chapter 4 Chemistry and Hazards of Hazardous Materials and Weapons of Mass Destruction

Chapter 4Chemistry and Hazards ofHazardous Materialsand Weapons ofMass DestructionCase HistoryA cargo tank carrying styrene was involved in a serious accident on a busy highway in a highlypopulated area. A haz mat team was called to the scene. Visual assessments and detection andmonitoring determined that the tank had not breached and no leaks had occurred.The chemical company responsible for shipping the styrene was contacted, and it was determined that the styrene was shipped with a time-sensitive inhibitor. This meant that the naturalpolymerization of the styrene would eventually overcome the inhibitor, potentially resultingin a rapid, runaway polymerization reaction. This set a timetable for mitigation of the incidentthat was under 24 hours.Plans for a worst-case scenario were developed and preliminary evacuations conducted. Untilthe chemical shipper’s own emergency response personnel arrived at the scene to take over,the haz mat team monitored the tank with a temperature gun to detect any rapid changes intemperature that might indicate an accelerating reaction.While it is not critical for hazardous materials technicians to be chemistry experts, some knowledge of chemistry can help hazardous materials technicianscomprehend how and why chemicals behave the way they do. This is an important skill-set, especially when reference sources are not immediately available.This chapter provides a brief and basic introduction to chemistry — enoughto address terminology and concepts that will make it easier to understand thebehavior of hazardous materials. As much as possible, these concepts are presented in terms of what it means to the hazardous materials technician in thefield. For example, the Periodic Table of Elements (also known as the PeriodicTable) is examined to provide clues that may help responders predict how various elements will behave.Examples provided in the chapter are used to illustrate concepts and arenot meant to be all-inclusive. For instance, in presenting the Periodic Table ofElements, the chapter highlights four “families” of elements that have similarcharacteristics and then explores one or two elements within each family.Out in the field, hazardous materials technicians must be diligent aboutchecking reference sources rather than relying solely on generalizations in thisbook or any other.Chapter 4 Chemistry and Hazards of Hazardous Materials and Weapons of Mass Destruction145

This chapter explores the following topics:A Helium AtomProtonNucleusNeutron Atoms and moleculesThe Periodic Table of ElementsFour significant familiesMatterBondingReactionsCommon families of hazardous materialsRadiationAtomsThe basic building block of any substance is the atom.Every element and compound is made up of one orElectronmore atoms. Each atom consists of several differentparts. At the center of the atom is a nucleus or coreFigure 4.1 A helium atom has two protons, two neutrons, andconsisting of protons, which are positively charged,two electrons in the electron shell. Because it has the sameand neutrons that have no charge. Electrons orbit thenumber of protons and electrons, it is electrically neutral.nucleus. These electrons reside in shells, sometimescalled orbits, orbitals, or rings (Figure 4.1). How elements interact with one anAtom — Basic unit of matterother is primarily a function of their electrons. A pure atom of an element hasconsisting of a nucleusthe same number of protons and electrons and the atom is electrically neutral.surrounded by a cloud ofElectronShellelectrons.Nucleus — Center of an atom,consisting of protons andneutrons.Proton — Subatomic particlethat possesses a positiveelectric charge.Neutron — Part of the nucleusof an atom that has a neutralelectrical charge and a massslightly larger than a proton.Electron — Minute componentof an atom that possesses anegative charge.Shells — The distance ororbit of electrons around thenucleus; shape of the electroncloud. Also known as Orbits,Orbitals, or Rings.146Elements differ from one another by the number of protons in the nucleus.For example, hydrogen always has one proton in its nucleus, oxygen always haseight protons, and sulfur always has sixteen protons. Some elements have anequal number of protons and neutrons, but it is not unusual for elements to havemore neutrons than protons. For example, sodium (atomic number 11) has elevenprotons and twelve neutrons. Hydrogen, the smallest of all elements, is an oddity;its dominant form has one proton but no neutrons (Figure 4.2).The atomic number of an element is the number of its protons. The number ofprotons always equals the number of electrons in an atom. The atomic mass isthe weight of an atom. It is determined by the number of neutrons and protonsthat are present in the nucleus.Periodic Table of ElementsThe Periodic Table of Elements is a tool for organizing and displaying the elementsin a way that provides some basic information about their characteristics. Thefirst 92 elements are found in nature and the remainders are manmade. As such,the periodic table continues to evolve as new elements are created and named.Figure 4.3, p. 148, is one version of the table that is commonly used. There areother tables that show different numbers of elements, but the differences that existbetween periodic tables are not significant to the hazardous materials technicianbecause they involve elements not likely to be encountered.Once the organization of the periodic table is understood, it can be usedquickly to obtain a wealth of information about any of the more than 112 elements. However, to realize its full potential as a valuable chemical resource, itis necessary to understand its organization. The elements of the periodic tableare arranged horizontally by order of increasing atomic number. Notice that theChapter 4 Chemistry and Hazards of Hazardous Materials and Weapons of Mass Destruction

table consists of several horizontal rows. These horizontalrows are called periods. The vertical rows found in theperiodic table are called groups, or families (Figure 4.4,p. 149). Elements within a specific group have similarchemical properties. As discussed in the next section, thesimilar chemical properties of elements within a groupoccur because these elements have the same number ofelectrons in their outer shells. These groups can be dividedinto three categories: metals, nonmetals, and metalloids.The diagonal line (that resembles a staircase) in the rightside of the periodic table separates the metals from thenonmetals (Figure 4.5, p. 150).Each element in the periodic table is identified by name,symbol, atomic number, and atomic weight (Figure 4.6,p. 151). A key feature of the periodic table is the dividingline between metals and nonmetals (Figure 4.7, p. 151).Metals are located on the left side of the periodic table;nonmetals are located on the right. (Hydrogen, which islocated in the upper-left corner above the thick dividingline, is also a nonmetal.) Metalloids and semiconductorsare the materials that straddle that line. Elements 113through 118 are artificial or synthetic elements createdin laboratories.Neutrons, Protons, and ElectronsHydrogenSodiumProtonNeutronElectronFigure 4.2 The atomic number of an element is the sameas its number of protons, so hydrogen is 1, and sodium is11. This is also the number of electrons. The number ofprotons and neutrons do not always match.Elements are arranged in the periodic table in order by atomic number. However, for the most part, as the atomic number increases, so does the atomic weight.Therefore, when considering the hazardous properties of individual elements,the hazardous materials technician can predict that elements lower on the periodic table will be solids and those higher on the table will be gases (Figure 4.8,p. 152). The weight of an element or compound becomes important when evaluating vapor density, specific gravity, and other related properties.Element — Most simplesubstance that cannot beseparated into more simpleparts by ordinary means.There are three major regions or areas on the periodic table. The representativeelements on either side of the table are the most important to the study of hazardous materials. As a category, they are more chemically active and encounteredmore often than the transition metals and the rare earth elements.Four Significant FamiliesElements are arranged vertically in groups called families based on their chemicalstructure. All members of the same family have similar chemical characteristics,though each has unique properties. Four families are significant because theyare the most predictable (Figure 4.9, p. 152): Group I — Alkali metalsGroup II — Alkaline earthsGroup VII — HalogensGroup VIII — Noble gasesHazardous materials technicians can make generalizations about elementsthat comprise each family prior to — not in lieu of — checking reference sourcesand trust that the differences between the elements are not so significant that anyone will be led astray. Table 4.1, p. 153, provides a summary of the four families.The following briefly describes each family with one or two specific examples.Chapter 4 Chemistry and Hazards of Hazardous Materials and Weapons of Mass Destruction147