Chapter 2: Atoms, Molecules & Life Atoms, Molecules & Life .
Chapter 2: Atoms, Molecules & LifeChapter 2:What Are Atoms?Atoms, Molecules & LifeAnswer: The smallest unit of matterComposed of:1) Nucleus (in the middle) Protons (positively charged particles) Neutrons (neutrally charged particles)2) Electrons (negatively charged particles) Orbit the nucleusAn atom is electrically neutral (protons electrons)Figure 2.1 – Audesirk2 & ByersChapter 2: Atoms, Molecules & LifeChapter 2: Atoms, Molecules & LifeElement Substance that can’t be broken down or converted to anothersubstance (via normal chemical means )Chapter 2: Atoms, Molecules & LifeIsotope The same element witha different number ofneutrons C14 P32 U235Radioactivity:Atoms spontaneouslybreak apart over time (Link)Atomic Number Number of protonsin the nucleusPeriodic Table of Elements:Atomic Mass Number of protons &neutrons in nucleusChapter 2: Atoms, Molecules & LifeRadioactivity in Research:Radiocarbon Dating:C12O2Positron Emission Tomography:C14O2PETscan Technique for determining the age of materialsthat contain carbon based on C14 levels1 C14 for every1,000,000,000,000 C12Half-lifeFigure E2.1 – Audesirk2 & Byers1
Chapter 2: Atoms, Molecules & LifeChapter 2: Atoms, Molecules & LifeElectrons Dictate Interactions Among Atoms:Periodic Table of Elements:Element Substance that can’t be broken down or converted to anothersubstance (via normal chemical means )2) CarbonB) are attracted to the nucleus ( charge)Electrons orbit the nucleus in 3-dimensional space forming electron shells:Key Elements in Living Organisms:1) Oxygen Electrons are: A) repelled from one another (- charge)3) Hydrogen4) Nitrogen First shell (2 electrons) Second shell (8 electrons) Third shell (8 electrons)OctetRule nth shell (8 electrons)Table 2.1 – Audesirk2 & ByersFigure 2.2 – Audesirk2 & ByersChapter 2: Atoms, Molecules & Life(link)Chapter 2: Atoms, Molecules & LifeElectrons Dictate Interactions Among Atoms:Life Depends on the Ability of Electrons to Capture / Release Energy:Question:You are throwing a birthday party and have the option of filling balloonswith a) hydrogen gas or b) helium gas. Both are less dense than regularair, and both cost the same. Based on their atomic structure, which doyou choose and why?Answer: NOT HydrogenFigure 2.3 – Audesirk2 & ByersChapter 2: Atoms, Molecules & LifeChapter 2: Atoms, Molecules & LifeElectrons Dictate Interactions Among Atoms:Reactive Atoms:Atoms with their outermostshell only partially filledHow would you make these atoms stable?Full outershellsInert Atoms:Atoms with their outermostshell either completely full or emptyCarbonNeonOxygenArgonSodium (neutral)Chloride (neutral)NitrogenRadon( )(-)Figure 2.4 – Audesirk2 & Byers2
Chapter 2: Atoms, Molecules & LifeChapter 2: Atoms, Molecules & LifeElectrons Dictate Interactions Among Atoms:Electrons Dictate Interactions Among Atoms:Chemical Bonds: Interaction of atoms to stabilize their outermost electronshells (attractive force)Types of Chemical Bonds: Molecule 2 or more atoms of any type held together by interactiveforces1) Ionic Bond: Attractive force between atoms that have lost or gainedelectrons (ions charged molecules)Water (H2O)HHHOtransferredelectronHTransfer ofelectronsHydrogen (H2) Compound 2 or more atoms of different types held together byinteractive forcesChemical Reaction: Making or breaking chemical bonds Essential for life (and modern society )Figure 2.4 – Audesirk2 & ByersChapter 2: Atoms, Molecules & LifeChapter 2: Atoms, Molecules & LifeElectrons Dictate Interactions Among Atoms:Electrons Dictate Interactions Among Atoms:Types of Chemical Bonds:Types of Chemical Bonds:1) Ionic Bond: Attractive force between atoms that have lost or gainedelectrons (ions charged molecules)2) Covalent Bond: Attractive force between atoms that share electronsSharing ofelectronsMost biological molecules utilizecovalent bonding:ProteinsCarbohydratesLipidsNucleic AcidsHydrogen (H2)Ionic Bonds Weak BondsCovalent Bonds Strong BondsFigures 2.4 & 2.5 – Audesirk2 & ByersChapter 2: Atoms, Molecules & LifeFigure 2.6 – Audesirk2 & ByersChapter 2: Atoms, Molecules & LifeExamples of Covalent Bonds:Common Covalent Bonding Patterns in Biological Molecules:Single Covalent Bond:Share one pair of electrons (e.g., H2)H-HDouble Covalent Bond:Share two pairs of electrons (e.g., O2)O OTriple Covalent Bond:Share three pairs of electrons (e.g., N2)N NTable 2.3 – Audesirk2 & Byers3
Chapter 2: Atoms, Molecules & LifeChapter 2: Atoms, Molecules & LifeExamples of Covalent Bonds:Electrons Dictate Interactions Among Atoms:Types of Chemical Bonds:Non-polar Covalent Bond:3) Hydrogen Bond: Attractive force between polar molecules (e.g., water)Equal sharing of electrons (e.g., H2)Due to polar covalent bonds:Polar Covalent Bond:Positive end of water molecule(H’s) attract negative end (O)of other water moleculeUnequal sharing of electrons (e.g., H2O)Molecule is electrically neutralBUTHydrogen Bonds Weak BondsPoles are charged due to differencesin nuclear attraction for electronsFigure 2.6 – Audesirk2 & ByersChapter 2: Atoms, Molecules & LifeChapter 2: Atoms, Molecules & LifeImportance of Water:1) Water is an excellent solvent: Liquid capable of dissolving other substances in itselfExample:Dissolving ionic bonds (salt)Water Good Stuff!Polar nature of waterLife most likely arose in waterLiving organisms 60 - 90% waterWhy is Water so Important to Life?Solution:Fluid containingdissolved substancesFigure 2.6 – Audesirk2 & ByersChapter 2: Atoms, Molecules & LifeChapter 2: Atoms, Molecules & LifeImportance of Water:Importance of Water:1) Water is an excellent solvent:2) Water molecules tend to stick together (cohesion): Liquid capable of dissolving other substances in itself Surface Tension: Tendency of a water surface to resist breakingWater-lovingExample:Dissolving polar bonds (sugar)LinkHydrophilic Molecules:Molecules electricallyattracted to waterMolecules tend toclump together inwater(ions / polar molecules)Water-fearingHydrophobic Molecules:Molecules electricallyneutral Adhesion: Tendency of water to stick to walls of surfacesFlow againstgravity(fats / oils)4
Chapter 2: Atoms, Molecules & LifeChapter 2: Atoms, Molecules & LifeImportance of Water:The pH of a solution describes its degree of acidity:3) Water can form H and OH- ions (ionization):Figure 2.14 – Audesirk2 & ByersH OH-H2OPure water contains equal amounts of H and OH-HClAcidicBasicNaOHH OH-H H OH- OH-H WaterOH-WaterFigure 2.15 – Audesirk2 & ByersChapter 2: Atoms, Molecules & LifeChapter 2: Atoms, Molecules & LifeBuffers maintain a solution at relatively constant pH:Importance of Water: Stable pH essential for normal function (Human body 7.3 – 7.4)4) Water moderates temperature changes: Buffers either accept or release a H in response to changes in pHBackground:Example: Bicarbonate ion (HCO3-) Temperature Speed of molecules Slow molecules Cool temperaturesToo acidic? Fast molecules Warm temperaturesHCO3- H Bicarbonate ionH2CO3Hydrogen ionCarbonic Acid Energy first initiates breaking of hydrogen bonds Specific Heat Energy needed to heat 1 g of a substance 1 CToo basic?H2CO3 OHCarbonic AcidHydroxide ionA) Water heats slowlyHCO3- H20 Specific HeatWater 1 calBicarbonate ion Specific HeatGranite 0.02 calWater Specific HeatAlcohol 0.6 calChapter 2: Atoms, Molecules & LifeImportance of Water:3) Water moderates temperature changes:B) Water is an effective coolant Heat of Vaporization: Heat needed to convert liquid water to watervapor 529 calories / gram (very high!)C) Water freezes slowly Moderates the effects of lowtemperaturesD) Water forms iceBy evaporating 1 g of water,539 grams of human body cools 1 C Less dense than liquid (unusual )5
Neutrons (neutrally charged particles) 2) Electrons (negatively charged particles) Orbit the nucleus An atom is electrically neutral (protons electrons) Chapter 2: Atoms, Molecules & Life Figure 2.1 –Audesirk2 & Byers Periodic Table of Elements: Element Substance that can’t
A. 1.13 1024 atoms B. 1.48 1025 atoms C. 2.44 1022 atoms D. 3.22 1023 atoms E. 6.98 1021 atoms 50. How many atoms are in 7.12 mol of gold, Au? A. –1.18 10 23 atoms B. 244.29 10 atoms C. 8.46 1022 atoms D. 4.70 1024 atoms E. 3.34 1026 atoms 51. How many moles are
CARBON-BASED MOLECULES Reinforcement KEY CONCEPT Carbon-based molecules are the foundation of life. Carbon atoms are the basis of most molecules that make up living things. Many carbon-based molecules are large molecules called polymers that are made of many smaller, repeating molecules called monomers. There are four main types of
Part One: Heir of Ash Chapter 1 Chapter 2 Chapter 3 Chapter 4 Chapter 5 Chapter 6 Chapter 7 Chapter 8 Chapter 9 Chapter 10 Chapter 11 Chapter 12 Chapter 13 Chapter 14 Chapter 15 Chapter 16 Chapter 17 Chapter 18 Chapter 19 Chapter 20 Chapter 21 Chapter 22 Chapter 23 Chapter 24 Chapter 25 Chapter 26 Chapter 27 Chapter 28 Chapter 29 Chapter 30 .
Atoms, Molecules, and Ions The theory that atoms are the fundamental building blocks of matter reemerged in the early 19th century, championed by John Dalton. Dalton's Postulates Each element is composed of extremely small particles called atoms All atoms of a given element are identical to one another in mass and other
TO KILL A MOCKINGBIRD. Contents Dedication Epigraph Part One Chapter 1 Chapter 2 Chapter 3 Chapter 4 Chapter 5 Chapter 6 Chapter 7 Chapter 8 Chapter 9 Chapter 10 Chapter 11 Part Two Chapter 12 Chapter 13 Chapter 14 Chapter 15 Chapter 16 Chapter 17 Chapter 18. Chapter 19 Chapter 20 Chapter 21 Chapter 22 Chapter 23 Chapter 24 Chapter 25 Chapter 26
AJR Ch2 Atoms, Molecules and Ions.docx Slide 1 Chapter 2: Atoms, Molecules, and Ions (Ch2 Chang, Chs 0 and 2 Jespersen) Atoms are the basic building blocks of matter. They are the smallest particles of an element that retain the chemical identity of the element, or, the basic unit of an element that can enter into chemical combination.
atoms held together by chemical bonds. Example: Table salt, NaCl Also the smallest unit of a compound. Not all molecules are compounds. H2, O 2, and other diatomic gases are not molecules. Why? 3 How are molecules formed? The number of electrons in the outermost electron shell determine whether an atom is reactive or inert. Carbon .
In accepting this appointment, you confirm that you are able to allocate sufficient time to meet the demands of your role as described in this letter. We ask that the agreement of the Chairman of Anglian Water Services Limited (the “Chairman”) be sought, such consent not to be unreasonably withheld or delayed, before accepting additional commitments that might impact on the time you are .
