1 / 27

Chapter 2

Chapter 2. Life’s Chemical Basis. The Basics. Matter—anything that has mass and takes up space Solid Liquid Gas. The basics. Element—unit of matter than cannot be broken down further by ordinary chemical reactions 92 naturally occurring elements

aleda
Download Presentation

Chapter 2

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Chapter 2 Life’s Chemical Basis

  2. The Basics • Matter—anything that has mass and takes up space • Solid • Liquid • Gas

  3. The basics • Element—unit of matter than cannot be broken down further by ordinary chemical reactions • 92 naturally occurring elements • 98% of weight of any living thing is made up of 6 • Carbon • Hydrogen • Oxygen • Nitrogen • Phosphorous • Sulfur

  4. Building blocks • Atom—smallest indivisible unit of an element • Molecule—multiple atoms of the same element bonded together • Compound—multiple atoms of different elements bonded together

  5. Atoms • Three subatomic particles • Protons • Neutrons • Electrons

  6. Bohr model

  7. Bohr model

  8. Bohr model

  9. Electron orbits • Orbit in “shells” • K Shell—2 electrons • L Shell—8 electrons • M Shell—18 electrons

  10. Periodic chart • Atomic Number=Protons • Atomic Mass=Protons + Neutrons

  11. Periodic chart • Elements in their natural state have neutral charge • Positive charge (protons) equals negative charge (electrons)

  12. isotopes • Change in the number of neutrons • Does not affect charge • Carbon-14 • Atomic Mass = 14 (6 Protons + 8 Neutrons) • Radioisotopes in medical diagnosis

  13. ions • Change in the number of electrons • Affects charge • Anion—negative charge • More electrons than protons • Cation—positive charge • More protons than electrons

  14. bonds • Ionic • Covalent • Hydrogen

  15. Inert elements

  16. Active elements

  17. Ionic bonds • Formed between ions • Electrons transfer from one atom to another • Opposite charges attract and hold atoms • Usually inorganic (acids, bases, salts, etc.)

  18. Covalent bonds • Atoms share electrons • Happens when both have room • Usually organic (proteins, carbohydrates, etc.)

  19. Covalent vs. ionic

  20. Hydrogen bonds • Bond between covalently bonded hydrogen atom & atom in different molecule or different location. • Individually weak, but collectively strong.

  21. water • Biologically important • Makes up 70-90% of living things • Unique properties

  22. water • Polar molecule (slight positive & negative charge) • Can easily dissolve other polar molecules • Hydrophilic • Hydrophobic • “universal solvent” • Cell membranes • Temperature stabilizing • Keeps cell processes from generating too much heat • Evaporation • Ice helps insulate

  23. water • “Stick together” • Adhesion—water sticks to itself • Cohesion—water sticks to other polar molecules • Due to polarity & hydrogen bonds

  24. acidity • pH scale • 0-14 • Based on H+ & OH- molecules • Greater H+, lower the pH • Each unit is 10-fold change • going from pH 6 to 5 increases H+ by 10 times

  25. Acidity • Acids • Donates H+ • pH less than 7 • Bases • Accepts H+ • Releases OH- • pH greater than 7 • Neutrals • Release equal numbers of H+ and OH- • pH 7.0

  26. Acidity • Buffers • Biological substances that help regulate pH • Release or absorb H+ to keep pH unchanged • Ex.—Carbonic Acid, Bicarbonate regulate blood H2CO3 + OH- HCO3- + H20 HCO3- + H+ H2CO3

More Related