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Transcript
Composition of Matter Atom= building block of an element Smallest part of matter Protons= + charge Neutrons= 0 charge Electrons= -1 charge Protons & neutrons= IN NUCLEUS Electrons= Orbit OUTSIDE nucleus Subatomic Particles Proton: positive charge, +1 mass, in nucleus Neutron: no charge, +1 mass, in nucleus Electron: negative charge, 0 mass, outside nucleus ***# of protons ALWAYS = # Electrons Identifying Elements: Atomic Number: number of protons in an element Zr=40 protons…and _______electrons Mass Number: Protons + neutrons H= 1 mass # He=4 mass # Sodium Mass Number = 23 Atomic number = 11 + 11p 12n 2-8-1 23 protons & neutrons - 11 protons __________________ 12 neutrons In a neutral sodium atom the number of protons (11) = the number of electrons (11) Beryllium Mass Number = 9 Atomic number = 4 + 4p 5n 2-2 9 protons & neutrons - 4 protons __________________ 5 neutrons In a neutral beryllium atom the number of protons (4) = the number of electrons (4) Nitrogen Mass Number = 14 Atomic number = 7 + 7p 7n 2-5 14 protons & neutrons - 7 protons __________________ 7 neutrons In a neutral nitrogen atom the number of protons (7) = the number of electrons (7) Sulfur Mass Number = 32 Atomic number = 16 + 16p 16n 2-8-6 32 protons & neutrons - 16 protons __________________ 16 neutrons In a neutral sulfur atom the number of protons (16) = the number of electrons (16) Silicon Mass Number = 28 Atomic number = 14 + 14p 14n 2-8-4 28 protons & neutrons - 14 protons __________________ 14 neutrons In a neutral silicon atom the number of protons (14)= the number of electrons (14) Potassium Mass Number = 39 Atomic number = 19 + 19p 20n 2 - 8 - 8- 1 39 protons & neutrons - 19 protons __________________ 20 neutrons In a neutral potassium atom the number of protons (19) = the number of electrons (19) Periodic Table Columns on the table are called Groups Group # is # of valence electrons Rows are called Periods Period # tells how many shells you have Atomic Weight & Isotopes Isotopes= same # of protons & electrons, but DIFFER in neutrons Ex) Hydrogen, H2, H3 They still have same chemical properties Radioisotopes= heavier isotopes that are unstable and decay Can be harmful to cells Can be used to tag biological molecules Chemical Compounds Chemical combination of 2 or more elements Water = H2O A compound can behave differently than the elements that make it up Ex) Water. Hydrogen is gas, Oxygen is gas. Together they form a liquid. Types of Chemical Bonds: Ionic Bond: when electrons are transferred from one element to another When an atom gains electrons, it becomes negatively charged and is called Anion. Cation = positive charge, when element gave up electron Covalent Bonds: When atoms share electrons The valence shell is satisfied by both molecules Van der Waals Forces When atoms share electrons, sharing is not always equal. + and – charges attract to each other Water Polarity Because of unequal distribution of electrons, water is polar. Negative pole of oxygen is attracted to the positive pole of hydrogen Solutions & Suspensions Solutions=all components in a mixture are equally distributed Suspensions= mixture of water and undissolved solutes Solute=substance dissolved Solvent=dissolves solute Acids and Bases Acids=produces H ions Value below 7 Bases=produce OH ions Value above 7 Look on pg. 43 pH Scale Created to indicate the concentration of H ions. Low # = acid High #= base Carbon Compounds Organic Chemistry is the study of all compounds containing carbon Carbon can form millions of different bonds 4 types of compounds: Carbs Lipids Nucleic acids Proteins Carbs= main source of energy Proteins= form bones, muscles, made of amino acids Nucleic Acids= store/transmit genetic information Lipids= store energy, make up membranes