PowerPoint ® Lecture Slide Presentation by Patty Bostwick-Taylor, Florence-Darlington Technical College Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings PART A 2 Basic Chemistry

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Matter  Biochemistry- the specialized area of chemistry that deals with living organisms and life processes  Matter—anything that occupies space and has mass (weight)

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Energy  Energy—the ability to do work or put matter in motion  Kinetic- when energy is doing work, moving objects  Potential- when energy is inactive or stored

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Energy  Forms of Energy  Chemical- stored in bonds  Electrical- results from movement of charged particles  Mechanical- energy directly involved in moving matter  Radiant- travels in waves  X-ray  Infrared  Radio waves  heat

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Composition of Matter  Elements—fundamental units of matter  96% of the body is made from four elements  Carbon (C)  Oxygen (O)  Hydrogen (H)  Nitrogen (N)  Others present in trace amounts  Atoms—building blocks of elements

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Atomic Structure  Nucleus  Protons (p + )  Neutrons (n 0 )  Outside of nucleus  Electrons (e - ) Figure 2.1

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Atomic Structure of Smallest Atoms Figure 2.2

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Identifying Elements  Atomic number—equal to the number of protons that the atom contains  Indirectly related to the number of electrons  Atomic mass number—sum of the protons and neutrons  Only nucleus has mass

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Isotopes and Atomic Weight  Isotopes  Have the same number of protons  Vary in number of neutrons Figure 2.3

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Isotopes and Atomic Weight  Atomic weight  Close to mass number of most abundant isotope  Atomic weight reflects natural isotope variation

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Radioactivity  Radioisotope  Heavy isotope  Tends to be unstable  Decomposes to more stable isotope  Radioactivity—process of spontaneous atomic decay  When we are exposed to radiation it knocks electrons out of their shell and may kill the cell  Alpha radiation is the weakest  Gamma radiation is the strongest

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Molecules and Compounds  Molecule—two or more like atoms combined chemically  Compound—two or more different atoms combined chemically Figure 2.4

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Chemical Reactions  Atoms are united by chemical bonds  Atoms dissociate from other atoms when chemical bonds are broken

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Electrons and Bonding  Electrons occupy energy levels called electron shells  Electrons closest to the nucleus are most strongly attracted  Each shell has distinct properties  The number of electrons has an upper limit  Shells closest to the nucleus fill first

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Electrons and Bonding  Bonding involves interactions between electrons in the outer shell (valence shell)  Full valence shells do not form bonds

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Inert Elements  Atoms are stable (inert) when the outermost shell is complete  How to fill the atom’s shells  Shell 1 can hold a maximum of 2 electrons  Shell 2 can hold a maximum of 8 electrons  Shell 3 can hold a maximum of 18 electrons

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Inert Elements  Atoms will gain, lose, or share electrons to complete their outermost orbitals and reach a stable state  Rule of eights or octet rule  Atoms are considered stable when their outermost orbital has 8 electrons  The exception to this rule of eights is Shell 1, which can only hold 2 electrons

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Inert Elements Figure 2.5a

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Figure 2.5b Reactive Elements  Valence shells are not full and are unstable  Tend to gain, lose, or share electrons  Allow for bond formation, which produces stable valence

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Chemical Bonds  Ionic bonds  Form when electrons are completely transferred from one atom to another  Ions  Charged particles  Anions are negative  Cations are positive  Either donate or accept electrons Ionic Bonds PLAY

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Ionic Bonds Figure 2.6 +– Sodium atom (Na) (11p + ; 12n 0 ; 11e – ) Chlorine atom (Cl) (17p + ; 18n 0 ; 17e – ) Sodium ion (Na + )Chloride ion (Cl – ) Sodium chloride (NaCl) ClNaCl Na

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Ionic Bonds Figure 2.6, step 1 Sodium atom (Na) (11p + ; 12n 0 ; 11e – ) Chlorine atom (Cl) (17p + ; 18n 0 ; 17e – ) Cl Na

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Ionic Bonds Figure 2.6, step 2 Sodium atom (Na) (11p + ; 12n 0 ; 11e – ) Chlorine atom (Cl) (17p + ; 18n 0 ; 17e – ) Cl Na

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Ionic Bonds Figure 2.6, step 3 +– Sodium atom (Na) (11p + ; 12n 0 ; 11e – ) Chlorine atom (Cl) (17p + ; 18n 0 ; 17e – ) Sodium ion (Na + )Chloride ion (Cl – ) Sodium chloride (NaCl) ClNaCl Na

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Covalent Bonds PLAY Chemical Bonds  Covalent bonds  Atoms become stable through shared electrons  Single covalent bonds share one pair of electrons  Double covalent bonds share two pairs of electrons

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Examples of Covalent Bonds Figure 2.7a

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Examples of Covalent Bonds Figure 2.7b

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Examples of Covalent Bonds Figure 2.7c

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Polarity  Covalently bonded molecules  Some are non-polar  Electrically neutral as a molecule  Some are polar  Have a positive and negative side Figure 2.8

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Chemical Bonds  Hydrogen bonds  Weak chemical bonds  Hydrogen is attracted to the negative portion of polar molecule  Provides attraction between molecules  Causes surface tension property of water and allows water to change states easily

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Hydrogen Bonds Figure 2.9

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Patterns of Chemical Reactions  Synthesis reaction (A + B  AB)  Atoms or molecules combine  Energy is absorbed for bond formation  Decomposition reaction (AB  A + B)  Molecule is broken down  Chemical energy is released

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Synthesis and Decomposition Reactions Figure 2.10a

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Synthesis and Decomposition Reactions Figure 2.10b

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Patterns of Chemical Reactions  Exchange reaction (AB + C  AC + B)  Involves both synthesis and decomposition reactions  Switch is made between molecule parts and different molecules are made

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Patterns of Chemical Reactions Figure 2.10c