Chapter 2 Chemistry Part 1.pptx

Chapter 2 Part 1 The Chemical Level of Organization  Atoms and Elements View Video: Chemistry Part 1 View Video: Chemistry Part 2 View Video: Ionic Bonding View Video: Covalent Bonding  Chemical Elements Elements are any substances that cannot be decomposed into sim...

Chapter 2 Part 1 The Chemical Level of Organization  Atoms and Elements View Video: Chemistry Part 1 View Video: Chemistry Part 2 View Video: Ionic Bonding View Video: Covalent Bonding  Chemical Elements Elements are any substances that cannot be decomposed into simpler substances - it’s the smallest amount of matter Elements are shown in the periodic table Of the 92 naturally occurring elements, 24 of them have biological role 6 elements = 98.5% of body weight – oxygen, carbon, hydrogen, nitrogen, calcium, and phosphorus Of the 98.5%, oxygen, carbon, hydrogen, and nitrogen make up 96% – The remainder 4% are made of lesser and trace elements the body needs Major Elements in Living Organisms  Chemical Elements Minerals—inorganic elements extracted from soil by plants and passed up food chain to humans – Ca, P, Cl, Mg, K, Na, and S – Constitute about 4% of body weight – Important for body structure (Ca crystals in teeth, bones, etc.) – Important for enzymes’ functions – Electrolytes—mineral salts needed for nerve and muscle function ©McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior written consent of McGraw-Hill  Atomic Structure Element - simplest form of matter to have unique chemical properties and characteristics Elements are composed of units of matter of the same type called atoms Atoms are the smallest units of matter that retain the chemical properties and characteristics of an element  Atomic Structure Atoms are composed of 3 subatomic particles: Protons - positive charge; mass of 1 Neutrons - no charge; mass of 1 Electrons - negative charge; no significant mass Atoms are identified by the specific numbers of protons, neutrons, and electrons they have Typically, the # protons = # neutrons = # electrons  Protons and Neutrons “hang out” together in Protons (p+) the nucleus at the center of the atom Nucleus Electrons orbit the nucleus in shells/orbitals Neutrons (n0) The first shell has 2 electrons The second shell has 8 electrons The third shell can have up to 18 Electrons (e–) electrons The Electrons Move Around the Nucleus So Fast, They Look Like a Cloud (a) Electron cloud model (b) Electron shell model  Copyright © McGraw-Hill Education. Permission required for reproduction or display. Bohr described the structure by comparing it to the Solar Carbon (C) Nitrogen (N) ,, ,, System, with Atomic number = 6 Atomic number = 7 planets moving Atomic mass Atomic mass = 12 = 14 around the Sun Sodium (Na) ,, Atomic number = 11 Atomic mass = 23 Bohr Planetary Models of Elements ©McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior Atomic Number and Mass Atomic number of an element is the number of protons in its nucleus Elements are arranged in the periodic table by atomic number Atomic Mass of an element is approximately equal to the atomic mass units (amu) of the total number of protons and neutrons Atomic Number is the Number of Protons and Elements are Arranged by Atomic Number  First Second electron electron shell shell 6p+ 7p+ 8p+ 1p+ 7n0 6n0 8n0 Carbon (C) Nitrogen (N) Oxygen (O) Hydrogen (H) Atomic number = 6 Atomic number = 7 Atomic number = 8 Atomic number = 1 Atomic mass = 12.01 Atomic mass = 14.01 Atomic mass = 16.00 Atomic mass = 1.01 Third Fourth Fifth electron electron electron shell shell shell 11p+ 17p+ 19p+ 53p+ 12n0 18n0 20n0 74n0 Sodium (Na) Chlorine (Cl) Potassium (K) Iodine (I) Atomic number = 11 Atomic number = 17 Atomic number = 19 Atomic number = 53 Atomic mass = 22.99 Atomic mass = 35.45 Atomic mass = 39.10 Atomic mass = 126.90 Atomic number = number of protons in an atom Atomic mass = number of protons and neutrons in an atom  Isotopes All atoms of an element have same number of protons and electrons BUT some atoms have 1 or 2 more neutrons Isotopes are atoms with different numbers of neutrons but same number of protons & electrons Reacts chemically in the same way  Isotopes Isotopes: Oxygen often forms isotopes O16, O17, and O18 numbers represent atomic weights Carbon forms isotopes - C12, C13, C14 Radioactive isotopes are unstable and decay, releasing energy or atomic fragments (atomic radiation) until they gain stability – equal number of protons and neutrons  Radioactive Isotopes Can harm us Intense radiation can be ionizing (ejects electrons, destroys molecules, creates free radicals) and can cause genetic mutations and cancer Examples: UV radiation, X-rays, alpha particles, beta particles, gamma rays  Radioactive Isotopes Can help us Nuclear medicine – MRI and CT – Uses injectable radioactive tracers to provide information about the functioning of specific organs – Radiation can be used to treat diseased organs or tumors Medical Uses of Isotopes Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 131 I concentrates in larynx thyroid thyroid gland trachea a. PET: positron- emission tomography b. a: © Biomed Commun./Custom Medical Stock Photo; b(Right): © Hank Morgan/Rainbow; b(Left): © Mazzlota et al./Photo Researchers, Inc  Molecules and Chemical Bonds Molecules – chemical substances composed of two or more of the same kind of atom united in a chemical bond O2 Compounds – molecules composed of two or more atoms of different elements H2O  Molecules and Chemical Bonds Molecular formula – Identifies the type of elements and shows how many of each are present  Chemical Bonds TABLE 2.3 Types of Chemical Bonds How are molecules and compounds made? Through Chemical bonds – forces that hold atoms together within a molecule or attract one molecule to another Types of Chemical Bonds – Ionic bonds – Covalent bonds – Hydrogen bonds  Atoms and Elements View Video: Ionic Bonds  Ions = Anions and Cations Some elements can give up or gain electrons Anion – atom that gained electrons and has a negative charge because it has gain a negatively charged electron Cation (pronounced “cat”ion) – atom that lost an electron and has a positive charge because it has more positively charged protons Give Up Electron Gain Electron  Ions = Anions and Cation Cations Anion Opposites Attract – So an Atom that Gives Up an Electron and is Positive is Attracted to Atom that Gained the Electron is Negative. They Create an IONIC BOND – An Attraction Bond  Electrolytes are Ions Atoms that have a positive or negative charge Electrolyte importance – chemical reactivity – osmotic effects (influence water movement) – electrical effects on nerve and muscle tissue Electrolyte balance is one of the most important considerations in patient care Common Ions in the Body  Ionic Bonds The attraction of a cation to an anion Once the electrons are donated by one and received by the other, the positive and negative charges are attracted to each other Relatively weak attraction that is easily disrupted in water, as when salt dissolves  Cl Na (c) Ionic bond in sodium chloride (NaCl)  Na+ Cl– (d) Packing of ions in a crystal of sodium chloride  Atoms and Elements View Video: Covalent Bonds  Covalent Bonds Formed by sharing electrons – the electrons orbit around both nuclei of the atoms Types of covalent bonds – single - sharing of 1 pair electrons – double - sharing of 2 pairs of electrons – triple – sharing of 3 pairs of electfons  Single Covalent Bond (a) Figure 2.6a ©McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior written consent of McGraw-Hill  Double Covalent Bond Carbon dioxide molecule (b ) Figure 2.6b ©McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior written consent of McGraw-Hill  Covalent Bonds Covalent bonds can be nonpolar or polar – nonpolar covalent bond shared electrons spend approximately equal time around each nucleus strongest of all bonds – polar covalent bond if shared electrons spend more time orbiting one nucleus than they do the other, they lend their negative charge to the area they spend most time  Nonpolar and Polar Covalent Bonds Copyright © McGraw-Hill Education. Permission required for reproduction or display. Nonpolar covalent bond (a ) Polar covalent bond (b ) Figure 2.7 ©McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior  Hydrogen Bonds Hydrogen bond – a weak attraction between a slightly positive hydrogen atom in one molecule and a slightly negative oxygen or nitrogen atom in another Water molecules are weakly attracted to each other by hydrogen bonds Very important to physiology – Protein structure – DNA structure  Hydrogen Bonding of Water Copyright © McGraw-Hill Education. Permission required for reproduction or display. Figure 2.8 ©McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior  d+ Hydrogen bonds d+ d–  Water View Video: Water Chemistry  Water Water is the most important compound in the body because nearly all of the body’s chemical reactions occur in water Water’s polar covalent bonds and its V-shaped molecule gives water a set of properties that account for its ability to support life – Solvency – Cohesion – Adhesion – Chemical reactivity – Thermal stability  Solvency Solvency - ability to dissolve other chemicals Water is called the Universal Solvent because it can dissolve chemicals - Due to its polarity – Hydrophilic (water loving) – substances that dissolve easily in water Molecules must be polarized or charged – Hydrophobic (water fearing)- substances that do not dissolve in water “Oily” type molecules that are not polarized or charged Water and Hydration Spheres Copyright © McGraw-Hill Education. Permission required for reproduction or display. Figure 2.9 ©McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior  H H O d– d– d– Na+ – d – d – d H H d– Water d– O molecule d– Hydrated sodium ion Na+ H O Cl – H d+ d + d+ Crystal of NaCl Cl– d+ d+ d+ Hydrated chloride ion  Solutions Solution—consists of particles called the solute mixed with a more abundant substance (usually water) called the solvent Solute can be gas, solid, or liquid Solutions will not separate on standing due to chemical bonds ©McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior written consent of McGraw-Hill  Water and Mixtures Mixtures – consists of substances physically blended, but not chemically combined (no chemical bonds) Most mixtures in our bodies consist of chemicals suspended in water  Adhesion and Cohesion Adhesion—tendency of one substance to cling to another – Water adheres to large membranes reducing friction around organs Cohesion—tendency of like molecules to cling to each other – Water is very cohesive due to its hydrogen bonds – Surface film on surface of water is due to molecules being held together by surface tension ©McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior  Chemical Reactivity Chemical reactivity—ability to participate in chemical reactions – Water ionizes into and – Water ionizes many other chemicals (acids and salts) – Water is involved in hydrolysis and dehydration synthesis reactions –more to come ©McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior  Thermal Stability High Specific Heat – Water can lose and gain large amounts of heat with little change in its own temperature – Enables the body to maintain a relatively constant temperature Hydrogen bonds keep water molecules from moving as much as other molecules which would increase the temperature of water  Water View Video: Acids and Bases  Acids, Bases and pH pH scale is a measure of concentration of H+ ion in moles in a liter (or molarity of H+) pH of 7.0 is neutral pH (H+ = OH-) – WATER – H2O “falls apart” H+ and OH- pH of less than 7 is acidic solution (H+ > OH-) pH of greater than 7 is basic solution (OH- > H+) A change of one number on the pH scale represents a 10-fold change in H+ concentration – A solution with pH of 4.0 is 10 times as acidic as one with pH of 5.0  The pH Scale Copyright © McGraw-Hill Education. Permission required for reproduction or display. Figure 2.11 ©McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior  Acids, Bases and pH An acid is proton donor - releases H+ ions in water A base is proton acceptor - accepts H+ ions and releases OH- ions in water  Buffers View Video: Buffers  Buffers To ensure homeostasis of the intracellular and extracellular fluids our body uses buffers to resist changes in pH – Homeostasis ranges for pH are very narrow and slight pH disturbances can disrupt physiological functions and alter drug actions  Buffers Example – pH of blood ranges from 7.35 to 7.45 – Deviations from this range cause tremors, paralysis or even death  Buffers Buffers minimize the changes in pH by either accepting H+ when in excess or releasing H+ when it is depleted There are many types of buffers that help to maintain pH stability in an organism  Acid–Base Balance View Video - Buffer System Carbonic acid-bicarbonate buffer system: this is based on the bicarbonate ion (HCO3–) which acts as a weak base, and carbonic acid (H2CO3) which acts as a weak acid If the pH falls, the HCO3– removes excess H+  Chemical Reactions Chemical reactions occur when chemical bonds form or break between atoms, ions, or molecules Reactants are the starting materials of a chemical reaction Products are substances formed at the end of the chemical reaction NaCl Na+ + Cl- (Reactant) (Products) Chemical equation – symbolizes the course of a chemical reaction  Metabolism View Video: Metabolism One of the characteristics of life was metabolism – The sum of all the chemical processes that occur in the body – Catabolism – breaking down of complex chemical substances into simpler components the body can use – Anabolism – building of complex chemical substances from small simpler components the body needs Metabolism Types of Chemical Reactions View Video: Chemical Reactions  Types of Chemical Reactions Synthesis Reaction: more complex chemical structure is formed A+B AB Decomposition Reaction: chemical bonds are broken to form a simpler chemical structure AB A+B Exchange Reaction: chemical bonds are broken and new bonds are formed AB + CD AD + CB Reversible Reaction: the products can change back Synthesis Reactions Anabolism Two or more small Amino acids molecules combine to form a larger one A + B AB Protein molecule  Decomposition Reactions Catabolism Large molecule breaks Starch molecule down into two or more smaller ones AB A + B Glucose molecules  Exchange Reactions Two molecules exchange atoms or group of atoms AB+CD ABCD AC + BD  Reversible Reactions Can go in either direction under different circumstances Symbolized with double-headed arrow A+B AB Law of mass action determines direction and proceeds from the side of equation with greater quantity of reactants to the side with the lesser quantity of products  Dehydration and Hydrolysis Reactions View Video: Dehydration and Hydrolysis Synthesis reaction or Anabolism are accomplished by dehydration reactions – Water is removed to form chemical bonds – Also called a condensation reaction Decomposition reaction or Catabolism are accomplished by hydrolysis reactions – Water is added to break chemical bonds Dehydration Reactions Joined Together Hydrolysis Reactions Broken Apart  For Tuesday’s Lecture Organic Compounds Organic Molecules: Organic Molecules Macromolecules: Macromolecules Biomolecules: Biomolecules