1 / 46

Atoms, Ions, and Compounds

Atoms, Ions, and Compounds. Section 2.1 Notes…. Atoms. The smallest unit of matter Three subatomic particles: Neutrons - no charge, in the nucleus, 1 atomic mass unit Protons - “+” charge, in the nucleus, 1 atomic mass unit Electrons - “-” charge, outside of nucleus, very small mass

lilly
Download Presentation

Atoms, Ions, and Compounds

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. Atoms, Ions, and Compounds Section 2.1 Notes…

  2. Atoms • The smallest unit of matter • Three subatomic particles: • Neutrons - no charge, in the nucleus, 1 atomic mass unit • Protons - “+” charge, in the nucleus, 1 atomic mass unit • Electrons - “-” charge, outside of nucleus, very small mass • ‘Normal’ atoms have same number of electrons as protons.

  3. Elements • Elements - a specific type of atom, defined by # of protons • on the periodic table • Isotopes - atoms of an element that have a different number of neutrons • Ions - atoms that have gained or lost electrons.

  4. Atomic Number = # of protons & # of electrons Atomic Mass = # of protons + # of neutrons On periodic table - average of isotopes Isotopes of an element have different atomic masses!

  5. Bohr Model • Shows subatomic particles • Copy the example from the board!

  6. Radioactive Isotopes • An isotope with an unstable nucleus breaks down to become more stable • Radioactive isotopes are used in medical imaging, carbon dating of fossils, and treatment of cancer, among other things!

  7. sToP & tHinK! • If an atom is neutral in charge, how does the number of electrons relate to protons? • What subatomic particle defines the identity of the atom? • Draw a Bohr model for Sulfur.

  8. Chemical Compounds • Two or more atoms bonded together • Two types of bonds and compounds: • Ionic - an electron is transferred • Covalent - two electrons are shared, a.k.a molecules

  9. Ionic Bond - electrons are transferred from one atom to another

  10. Covalent Bond - Two electrons are shared, by two atoms!

  11. Water! Section 2.2 Notes

  12. The Water Molecule • Hydrogens - more positive • Oxygens - more negative

  13. Molecular Interactions • Hydrogen bonding - attraction between positive hydrogen atom and a negative atom like oxygen or nitrogen. • Cohesion - attraction between molecules of the same substance • Adhesion - attraction between molecules of different substances

  14. sToP & tHinK • Which side of a water molecule would a sodium ion (Na+) be attracted to? • Which property is responsible for surface tension - cohesion or adhesion? Explain.

  15. Mixtures • Mixture - two or more elements or compounds combined physically • Solution - mixture is evenly distributed • solute - the substance that is dissolved • solvent - the substance dissolved into

  16. sToP & tHinK • If you make lemonade from a packet, what is the solute and what is the solvent? • Think of an example of a solution - identify the solute and solvent.

  17. pH Scale

  18. pH Scale • Range of 0 to 14 • less than 7 is acidic & has more H+ ions • more than 7 is basic/alkaline & has fewer H+ ions

  19. pH Scale • the pH affects the structure of molecules and their ability to function • human body pH range 6.5-7.5 • Buffers - help keep pH in a certain range

  20. sToP & THiNk! • Which has more H+ ions, a pH of 6.5 or a pH of 8.0? • Where do you think there are more H+ ions, in your mouth or in your stomach?

  21. Macromolecules -Carbon Compounds… 2.3 Notes

  22. Carbon… • Has 4 valence e-, so it can bond with up to four other atoms • Can form single, double, or triple covalent bonds • what are covalent bonds?

  23. <-- single bonds double bond -->

  24. sToP & tHinK • What are covalent bonds?

  25. Macromolecules • Polymers - large molecules made of repeating subunits • Monomers - the subunits that make up polymers • Four major categories of organic macromolecules: • carbohydrates, lipids, nucleic acids, & proteins

  26. Carbohydrates • sugars & starches • main source of energy for cells • Carbon:Hydrogen:Oxygen in 1:2:1 ratio • monosaccharides - monomer • polysaccharides - polymer

  27. Lipids • fats, oils, & waxes - hydrophobic! • used to store energy • major part of cell membranes

  28. sToP & tHinK • Lipids are made of long chains of carbon and hydrogen. They are hydrophobic. Based on this information, do you think lipids tend to be polar molecules? Explain.

  29. Nucleic Acids • Two types: RNA and DNA • Monomers = nucleotides • Nucleotides contain: 5-carbon sugar, a phosphate group, a nitrogenous base • Function: storage of genetic information

  30. Proteins • Monomer = amino acids • there are 20 major amino acids • sequence (or order) of amino acids determines the structure and function • proteins carry out instructions from DNA

  31. 3D structure of a protein determines its function. Proteins can’t work properlyif 3D structure is disrupted.

  32. SToP & THiNk Try to brainstorm some things that might affect the shape of a protein. These can be changes to the protein directly or by changing what it’s surrounded by. Example: changing the amount of salt

  33. Chemical Reactions & Enzymes 2.4-2.5 Notes

  34. Chemical Reactions • changes one substance into another • Always involves breaking bonds and forming new bonds • Reactants - starting materials • Products - ending materials

  35. Energy in Reactions • Activation Energy - the amount of energy needed to convert reactants to products.

  36. Activation Energy Diagram

  37. SToP & THiNk • Based on the drawing you made - do the products in that reaction have more energy or less energy than the reactants? • Where does energy go when it is released in a reaction? • Is mixing salt with water a chemical reaction? Explain.

  38. Enzymes • Catalyst - any substance that speeds up a reaction without being used up during the reaction • Lowers activation energy! • Enzymes - proteins that speed up reactions in cells (biological catalyst)

  39. Enzymes lower the activation energy for reactions

  40. Enzyme-Substrate Complex • substrate - the substance/molecule that the enzyme acts on • active site - where the enzyme and substrate interact

  41. SToP & THiNk • Contrast enzyme and catalyst. • Why are enzymes important in living things?

  42. Factors that Affect Enzymes • Inhibitors block or slow down enzyme activity by fillling the active site.

  43. Factors that Affect Enzymes • Factors like temperature, pH, and salinity can affect enzyme function by altering the enzyme conformation (shape).

  44. sToP & tHinK • How could to you test to see if a protein acts as an enzyme in a reaction? • Do you think all enzymes work best at the same conditions? Explain.

More Related