the chemistry of life: atoms and molecules =. pure substances that cannot be broken down into...
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The Chemistry of Life: The Chemistry of Life: Atoms and Molecules Atoms and Molecules
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Pure substances that cannot be broken down into simpler chemical entities by ordinary chemical reactions.
Pure substances that cannot be broken down into simpler chemical entities by ordinary chemical reactions.
ElementsElements
Periodic Table 112 known elements
Major Elements Comprising Major Elements Comprising the Biological Molecules of the Biological Molecules of
Living ThingsLiving Things
Major Elements Comprising Major Elements Comprising the Biological Molecules of the Biological Molecules of
Living ThingsLiving Things
• CCarbonarbon• HHydrogenydrogen• OOxygenxygen• NNitrogenitrogen• PPhosphorushosphorus• SSulfurulfur
Other Major Elements of Living Things
Other Major Elements of Living Things
• Calcium (Ca)Calcium (Ca)• Potassium (K)Potassium (K)• Chlorine (Cl)Chlorine (Cl)• Magnesium (Mg)Magnesium (Mg)
Some Important Trace Some Important Trace Elements of Living ThingsElements of Living Things
Some Important Trace Some Important Trace Elements of Living ThingsElements of Living Things
• Boron (B)Boron (B)• Cobalt (Co)Cobalt (Co)• Iron (Fe)Iron (Fe)• Copper (Cu)Copper (Cu)• Fluorine (F)Fluorine (F)• Zinc (Zn)Zinc (Zn)
An element is composed of atoms (0.1-1 nm in diameter)
Atom cluster of small particles (proton, neutron, electron)
Elements & AtomsElements & Atoms
Subatomic ParticlesSubatomic ParticlesSubatomic ParticlesSubatomic Particles
Protons (p +)
Neutrons (n o)
Electrons (e -)
Electron Shell Configurations of AtomsElectron Shell Configurations of Atoms
proton
neutron
electron
hydrogenatom
heliumatom
carbonatom
1p, 0n, 1e- 2p, 2n, 2e- 6p, 6n, 6e-
atomic number: number of p; #p = #e-
2He2e- and 2p
He
atomic mass (atomic wt.): sum of masses of p+nHe 2p + 2n, atomic mass = 4
4
2He
He
p + n e-
p = n = e- = Atomic number = Atomic mass =
C
Carbon Atom
C12 C13 C14stable stable isotope unstable- radioactive isotope
IsotopeIsotopeatoms that differ in the number of neutrons
12
6 C13
6 C14
6 C
C
MoleculeMoleculeTwo or more atoms held
together by chemical bondsOxygenOxygen OO2 2
NitrogenNitrogen NN22
AmmoniaAmmonia NHNH33
Carbon DioxideCarbon Dioxide COCO22
WaterWater HH22OO
MethaneMethane CHCH44
GlucoseGlucose CC66HH1212OO66
CompoundCompoundBinding two or more different kinds of elements together
NaClNaCl
CHCH44
CC66HH1212OO66
IonIon
An atom that has either gained or lost electrons
such that it exhibits a net charge
Na+
Cl-
Sodium (Na) Sodium (Na) AtomAtom
11 P+
12 No
Sodium (NaSodium (Na++) Ion) Ion
11 P+
12 No
+
Chlorine (Cl) Chlorine (Cl) AtomAtom
17 P+
18 No
Chloride (ClChloride (Cl--) Ion) Ion
17 P+
18 No
_
Some Examples of IonsSome Examples of Ions
HydrogenHydrogen HH++
PotassiumPotassium KK++
FluorideFluoride FF--
CalciumCalcium CaCa+2+2
MagnesiumMagnesium MgMg+2+2
HydroxideHydroxide OHOH--
BicarbonateBicarbonate HCOHCO33--
NitrateNitrate NONO33--
PhosphatePhosphate POPO44-3-3
AmmoniumAmmonium NHNH44++
Acetate CAcetate C22HH33OO22--
Complex IonsComplex Ions
Bond TypesBond Types:• Ionic• Covalent• Hydrogen
Ionic BondsIonic BondsTransfer of electron
17 P+
18 No
11 P+
12 No
Covalent Bonding:Covalent Bonding: electron sharing
O
HH
Covalent Bonding:Covalent Bonding: electron sharing
C
H
H
H
H
C
H
H
H
H
Hydrogen Bonding Hydrogen Bonding Between Water MoleculesBetween Water Molecules
Covalent bond
Hydrogen bond
Hydrogen Bonding Between Hydrogen Bonding Between Different MoleculesDifferent Molecules
Examples of Organic Examples of Organic MoleculesMolecules
Properties of WaterProperties of Water
1. High heat capacity-absorbs and releases large amounts of heat (land heats faster than water)
2. High heat of vaporization- sweat, cooling mechanism
3. Polarity solvent properties- universal solvent
4. Reactivity- hydrolysis and condensation (dehydration)
Polarity of Water Polarity of Water MoleculesMolecules
Chemical ReactionsChemical Reactions
A BA B
reactant reactant product product
Chemical SynthesisChemical Synthesis
AA ++ BB AABB
Chemical Chemical DecompositionDecomposition
AABB AA ++ BB
Chemical Chemical RearrangementRearrangement
AABB ++ CCDD AACC ++ BBDD
HH22OO OOHH- - ++ HH++
OOHH H
H+
Water molecule[H2O]
Hydroxyl ion[HO-]
Hydrogen ion[H+]
Decomposition of Decomposition of WaterWater
AcidsAcids
HCL H+ + Cl-
Proton donor, i.e., they donate H+ ions
HCl is a strong acid with a pH 1-2
BasesBases
Na+ + OH- NaOHNH3 + H+ NH4
OH - + H+ H2O
HCO3 +H+ H2CO3
Proton acceptor, i.e., they take up H+ ions
NaOH is a strong base ~pH 12
NeutralizationHCl + NaOH H2O + NaCl
Buffer- resists dramatic changes in pH; ex. tums, rolaids…buffers stomach acid
pH ScalepH Scale
Neutral 7Acidic 0-6Basic (alkaline) 8-14
Type of Solution pH Value
0-14
Logarithmic scale
pH ScalepH Scale
Inquiry
1. How many neutrons in 7 N?2. Of the following pH’s which is most
acidic? 3 7 6 23. The symbols K, Na, C, and S are:4. Which of the following are elements?water; sugar; table salt; the atmosphere
5. Which of the following are pure substances?
wine; seawater; blood; iron
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