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Chemistry of Life

Chemistry of Life. Biology Chapter 2. Elements. Substances that cannot be broken down chemically into simpler kinds of matter More than 100 types Organized on the periodic table of elements. Elements of Life. Approximately 27 are essential to life

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Chemistry of Life

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  1. Chemistry of Life Biology Chapter 2

  2. Elements • Substances that cannot be broken down chemically into simpler kinds of matter • More than 100 types • Organized on the periodic table of elements

  3. Elements of Life • Approximately 27 are essential to life • 90% of mass of living things are O, C, H, N • Elements of Life: CHONPS • Remember the Elephants in the Element Song?

  4. Atom • Smallest unit of an element that retains all the properties of that element

  5. Nucleus • Central region of an atom • Contains the bulk of the mass of the atom • Consists of protons and neutrons

  6. Proton • Positively charged particle • Located in Nucleus • Mass approximately 1 AMU http://www.fas.org/nuke/guide/usa/doctrine/dod/fm8-9/fig2-I.gif http://images.thecarconnection.com/med/proton-logo_100378711_m.jpg

  7. Neutron • Neutral charged particle, No Charge • Located in Nucleus • Mass approximately 1 AMU http://www.chem4kids.com/files/art/atom_neutron1.gif http://www.chem4kids.com/files/art/atom_struct1.gif http://d1jqu7g1y74ds1.cloudfront.net/wp-content/uploads/2010/02/c-atom_e1.gif

  8. Electron • Negatively charged particle • Orbits the nucleus in the electron cloud • Mass practically zero

  9. Orbitals • Electrons orbit in specific regions called orbitals- • 3D space higher probability location of orbital • Each orbital is associated with an energy level • Electrons in orbitals further from the nucleus have more energy

  10. Electron Orbitals & Energy Levels • Each orbital can hold 2 electrons • Each energy level consists of different #s of orbitals http://quantumnumbers.weebly.com/uploads/1/2/2/1/12213482/8009912_orig.jpeg

  11. Build an Atom

  12. Atomic Number • Number of protons in an atom • Determines type of element • Elements are organized by atomic number on the periodic table • Atomic Number for Carbon is 6

  13. Mass Number • Total number of Protons + Neutrons • Protons have mass of 1 amu • Neutrons have mass of 1 amu • Mass Number – Atomic Number = # of neutrons http://www.sawyerscience.com/assets/images/units/unit_2/atomic_Mass.jpg

  14. Mass Number http://1.bp.blogspot.com/-DFx20P3q3fw/TciZDNxjLQI/AAAAAAAAACU/BsGwZgYExOM/s1600/isotopes.jpg http://chemwiki.ucdavis.edu/@api/deki/files/8320/He_Atom.png

  15. Compounds • Made of atoms of two or more elements in fixed proportions • Chemical formula shows kinds and proportions of atoms • H2O - • C6H12O6 – • CO2- • CO - • O2- Compound?

  16. Molecule • Simplest part of a substance that retains all properties of that substance • Can exist in a free state • Can be very large- carbohydrates, lipids, proteins, nucleic acids (macromolecules) • H2O - • C6H12O6 – • CO2- • CO - • O2-

  17. Chemical Bonds • Attractive forces that hold atoms together • Covalent Bonds • Ionic Bonds • Hydrogen Bonds Stable Atom = Highest energy level filled

  18. Valence Electrons • Number of electrons in the highest energy level for that atom • Atoms are more stable when outer energy level is full (2 or 8 electrons depending on element)

  19. Dot Diagrams • Show the valence electrons on an atom • Hydrogen and helium only hold up to 2 valence electrons • Other elements (that we will look at) hold up to 8 valence electrons http://legacy.jyi.org/volumes/volume3/issue1/features/peterson.html http://webgenchem.com/lewishcn.gif

  20. Covalent Bond • Two atoms share one or more pairs of electrons http://faculty.clintoncc.suny.edu/faculty/michael.gregory/files/bio%20101/bio%20101%20lectures/chemistry/chemistr.htm

  21. Ion • Some atoms only need to gain or lose 1 or 2 electrons to be stable • Ions- Forms of an atom that have gained or lost electrons • Fills the outer shell of electrons • If electrons are gained, Ion is NEGATIVE (ANION) • If electrons are lost, Ion is POSITIVE (CATION)

  22. Ion Example • Sodium and Chlorine

  23. Ionic Bonding • Atoms form ions and become positive or negative • Opposite charges attract

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