Chapter+2+Review+1

=Group WorkChapter 2: The Chemical Context of Life= __Chemical Elements and Compounds:__ //Matter Consists of Chemical Elements in Pure Form and in Combinations Called Compounds -// 1. Matter - anything that takes up space or has mass 2. Element - substance that can't be broken down by other substances by chemical reactions 3. Compound - substance consisting of 2 or more elements combined in a fixed ratio //Life Requires About 25 Elements -// 4. Trace elements - those required by an organism in only minute quantities __Atoms and Molecules:__ //Atomic Structure Determines the Behavior of an Element -// 5. Atom - smallest unit of matter that still retains the properties of an element 6. Atomic Nucleus - center of atom, packed with neutrons and protons 7. Dalton - unit of measurement for atoms and subatomic particles 8. Atomic Mass - sum of protons and neutrons in an atom 9. Mass # - #of protons in an atom 10. Atomic Weight - approximation of the total mass of an atom 11. Isotope - all atoms of a given element have the same # of protons, but some atoms have more neutrons than other atoms of the same element and therefore weigh more 12. Radioactive Isotopes - 1 in which the nucleus decays spontaneously, giving off particles and energy 13. Energy - the ability to do work 14. Potential Energy - energy that matter stores because of it position or location 15. Energy levels - "electron shells", different states of potential energy that electrons have in an atom 16. Valence Electrons - electrons in the outermost shell 17. Valence Shell - outermost electron shell 18. Orbital - 3D space where an electron is found 90% of the time //Atoms Combine by Chemical Bonding to Form Molecules -// 19. Chemical Bonds - atoms held together by attraction 20. Covalent Bond - sharing of a pair of valence electrons by 2 atoms 21. Molecule - 2 or more atoms held together by covalent bonds 22. Structual Formula - represents both atoms and bonding 23. Molecular Formula - indicates a molcule consisting of 2 atoms 24. Double Covalent Bond - atoms that share 2 pairs of valence electrons 25. Valence - = the # of unpaired electrons in the atom's outermost shell 26. Electronegativity - attraction of an atom for the electrons of a covalent bond 27. Nonpolar Covalent Bond - = share of electrons 28. Polar Covalent Bond - one atom is bonded to a more electronegative atom, there isn't an = share of electrons 29. Ion - charged atom or molecule 30. Cation - charge is positive 31. Anion - charge is negative 32. Ionic Bond - cations and anions attract each other 33. Ionic Compund/Salt - compounds formed by ionic bonds //Weak Chemical Bonds Play Important Roles in the Chemistry of Life -// 34. Hydrogen Bond - forms when a hydrogen atom covalently bonded to an electronegative atom 35. Van Der Waals Interactions - everchanging "hotspots" of positive and negative charge that enable all atoms and molecules to stick to each other //Chemical Reactions Make and Break Chemical Bonds -// 36. Chemical Reactions - the making and breaking of chemical bonds, leading to changes in the composition of matter 37. Reactants - starting materials 38. Products - finishing materials //Bill Nye Videos on Molecules and Atoms// http://www.youtube.com/watch?v=PNjKVe7cC0Q http://www.youtube.com/watch?v=DtBm4MkpiJc&feature=related http://www.youtube.com/watch?v=QEMQLjbJ5bo&feature=related //Bill Nye Videos on Chemical Reactions// http://www.youtube.com/watch?v=_KGtLz081eI http://www.youtube.com/watch?v=rY2hSp1n6mA&feature=related http://www.youtube.com/watch?v=7TjxChL0SMA&feature=related //Video on atomic number, mass number, and isotopes// http://videos.howstuffworks.com/hsw/6294-atomic-number-mass-number-isotopes-video.htm
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