BIOL 102 1st Edition Lecture 1Chapter 2 - The Chemistry of Life- matter - anything that takes up space- element - anything that can’t be broken down by chemical means- 92 natural occurring elements- compound - 2 or more elements that combine in a fixed ratio- ex.) Water -> H2O -> Hydrogen 2 : Oxygen 1A. Life requires about 25 out of the 92 natural elements- 4 make up 96% of living matter- Carbon (C)- Hydrogen (H)- Oxygen (O) **most important because of water; there’s a lot of oxygen withinwater- Nitrogen (N)- Remaining 4%- Iron (Fe)( in anemia)- Iodine (I) (for the thyroid gland)- Nitrogen (N) (plants)B. CHNOPS- the top 6 elements for humans/organisms on Earth-Carbon-Hydrogen-Nitrogen-Oxygen-Phosphorus **important because of phosphate groups in proteins(ATP)-Sulfur **important because of amino acids and development of proteins- trace elements - elements in small quantities that we need-ex.) Iron, Iodine- too much/too little of trace elements can cause certain deficiencies **instructorhad iodine deficiencyC. Characteristics of Atoms- atomic number - # of protons- atomic mass - # of protons + neutronsThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.- subatomic particles - smaller particles in atoms- ex.) protons(positive charge), neutrons(no charge), electrons(negative charge)- electrons are like stalkers(stay on the outside)D. Isotopes- different atomic forms of the same element- same # of protons, but different # of neutrons and atomic massex.) carbon- has 6 protons; no other element has 6 protonsE. Carbon Isotopes- Carbon & Hydrogen have forms of isotopes- C12 & C13(most stable)- C14(least stable) - because they lose the most subatomic particles- C14 decays(breaks down) into Hydrogen- when an isotope decays, its labeled as a radioactive isotopeF. Uses for Radioactive Isotopes- fossil dating- measures radioactivity in other aspects of the Earth- MRI, CRI scans- the liquid you drink before certain medical scans is filled with radioactiveisotopes which allow for doctors to see any issues more clearly during the procedure.G. Electrons- electrons determine chemical behavior- electrons are on the outside( the outsides are called orbitals)- the 1st orbital can only hold 2 electrons- every orbital after the 1st can hold up to 8 electrons- octet rule- all atoms have a full orbital level of 8 electrons and nothing more- valence electrons - the electrons on the outermost orbitalH. Chemical Bonds Between Atoms- covalent- ionic- hydrogenI. Covalent Bonds- the sharing of the outermost electrons of two atoms- the ‘CHNOPS’ can each make a certain amount of covalent bonds- Carbon - 4- Hydrogen - 1- Nitrogen - 3- Oxygen -2- Phosphorus - 4- Sulfur - 2- it’s all about getting each atom to the full 8 electrons (fulfilling the octet rule)J. Pure Elements v.s. Compounds- compound- combo of two or more different elementsex.) Water -. H2O- pure - one element present(independently)ex.) Oxygen - 02 ; Hydrogen - H2K. Sharing Electrons in a Covalent Bond- single bonds (weakest)- the sharing of one electron- double bonds- the sharing of two electrons- triple bonds- the sharing of 3 electrons- Nitrogen loves to perform triple bondsL. Electronegativity- involves two atoms- one atoms has the potential to pull electrons to itself due to its electronegativityex.) Water -> H2O -> Oxygen is the more electronegative therefore it will attract aton of/ the most electronsM. Nonpolar Covalent Bond- two elements have the same electronegativityex.) bond between 2 atoms of the same elementex.) bond between carbon and Hydrogen- electrons shared equally because of electronegativityN. Polar Covalent Bond- one atom is more electronegative than the other- the electrons won’t be shared equallyex.) Water- because Oxygen is the most electronegative and will attract most of theshred electrons to itself- an unequal sharing will cause the more electronegative atoms to become more“partially negative” **negative symbolex.) Water- the oxygen in water would be considered at partially positive because ofis high electronegativity- the bond in a water molecule itself is a polar covalent bondO. Ionic Bonds- a result of ionization- the two atoms are so unequal in their attractions for the valence electrons, that themore electronegative atoms strips an electron away from its partner atom to another- permanent transfer of electrons from one atom to another- cation - positive ion- anion- negative ionex.) ionic compounds like table salt, NaCl, dissolves in water because theattractions can be broken down so easily that in water NaCL goes back to Na & CLindependently / respectivelyP. Hydrogen Bonds- weak bonds that attach hydrogen atoms covalently to a more electronegative atomwhich attaches to another more electronegative atomsex.) hydrogen bonds between water molecules in water- Oxygen becomes negative- Hydrogen becomes