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Chemistry of Life

Chemistry of Life. Composition of Matter. Matter. anything that occupies space and has mass. is the quantity of matter an object has. Mass vs. Weight Weight is determined by the force of gravity acting on a mass

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Chemistry of Life

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  1. Chemistry of Life

  2. Composition of Matter Matter anything that occupies space and has mass is the quantity of matter an object has Mass vs. Weight • Weight is determined by the force of gravity acting on a mass • Example: The same mass would have less weight on the moon than on the Earth Mass

  3. Elements and Atoms Elements are substances that cannot be broken down chemically into simpler kinds of matter . 90% of the mass of all living things are composed of just four elements: Carbon Hydrogen Oxygen Nitrogen Over 100 elements exist. Fewer than 30 are important for life

  4. ELEMENTS – organized in Periodic Table • chemical symbol- consists of 1,2,or 3 letters • derived from first letter or other letters in the name • Ex: Chlorine-Cl • Most other names are derived from Latin names

  5. ATOMS – simplest particles of an element that retains all the properties of that element Consist of 3 SUBATOMIC PARTICLES n Inside Nucleus Outside Nucleus

  6. # electrons = # protons in a NEUTRAL ATOM NUCLEUS - the central part of an atom and makes up the bulk of the mass of an atom

  7. ELECTRONS- are negatively charged particles found orbiting the nucleus of an atom • high energy –fast orbit • very little mass • located in orbitals or energy levels • Electrons in outer orbitals have more energy • 1st energy level can only hold 2 electrons • 2nd energy level can hold up to 8 electrons

  8. Isotopes-atoms of the same element that have a different number of neutrons

  9. Compounds- made up of atoms • of two or more elements in fixed proportions

  10. Chemical Formula • shows the kinds and proportions of atoms of each element that forms a particular compound 2 Hydrogen Atoms • H2O 1 Oxygen Atom

  11. So,when does bonding occur? • Elements will combine to form molecules or compounds if their outer energy level or orbital is NOT FILLED. • An atom is chemically stable when its highest energy level is filled with the maximum number of electrons. • These elements are called noble or inert elements (gases) and do not react with other elements under normal conditions. (Ex: Helium, Neon)

  12. CHEMICAL BONDS – attractive forces that hold atoms together

  13. Covalent Bonding - • form when two atoms • share one or • more pairs of electrons

  14. electrons in an atom’s outermost energy level = valence electrons • When outer shell is filled – atom is stable • Hydrogen has ______electron so it needs __________more to fill its first energy level to achieve stability

  15. Ionic Bonds- form from the attractive force between oppositely chargedions (charged particle) • Atoms gain or lose electrons to achieve stability • they become either positively charged or negatively charged • NaClis table salt and forms from a Na+ ion bonding with a Cl-ion

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