chemistry

• • Chemical Property is when you change the composition or change what it’s made out of
• • Physical Property is when you don’t have to change the composition
• Physical Property is when?

  You don't have to change the composition
• Independent variable: always changing
• Dependent variable: what's affected
• Controlled: should stay the same
• Particle: a small piece of something
• Atom: protons, neutrons, electrons are the smallest piece of matter that keep elemental property
• Element: every element has a unique set of properties
• Molecule: 2 (or more) atoms that are bonded together
• Chemistry: the study of chemicals
• Atomos: Indivisible, you can’t break it down any further 
• Electricity: motion of matter that has electric charge
• • A theory can never become a law and vice versa, tells you why a reaction happens
  • A law always works but doesn’t explain why
  • A theory is why, a law is what
• • All compounds are molecules but not all molecules are compounds
• • If a substance is changed in a way that the structure of its molecules is intact, it is a physical change
• • If the molecules of a substance are altered and made into completely different ones, it is a chemical change.
• • Law of conservation of mass: the matter stays the same but the form/composition can change
• • Signs of chemical reactions: heat radiation, absorption, light, different scents, bubbling, fizzing, different colors
• • Democritus was the first to figure out what atoms are/how they make everything up 
  • John Dalton was the first to find solid evidence of atoms, he also figured out there's always a particular ratio when you break things up, it's always even
  • Aristotle rejected Democritus’ theory on atoms, he believed everything is made up of fire, water, air and earth
  • JJ Thompson created the plum pudding model
  • Rutherford took positive alpha particles, shot it at gold and it would sometimes deflect
• • Like charges deflect
  • Ions are charged atoms
  • Cations are positive
  • Anions are negative
• • Valence electrons are the electrons on the outermost orbit of the Bohr Diagram
• • The first orbit can hold 2 electrons, the second can hold 8, the third can hold 8
• • If it has a charge put [] the diagram and the charge  (ex: [bohr diagram+1]) 
• • Atomic mass - protons = neutrons
• • Protons = electrons
• • Valence electron = column 
  • # of orbits = row
• • If there are more electrons it has a negative charge
  • If it loses an electron it has a +1 charge because it has that many more protons than electrons
  • If it gains an electron it has a -1 charge because it has more electrons than protons
• • Column 1 is all alkali metals, they are very reactive and only have 1 valence electron
  • Column 2 is all alkaline earth metals
  • Column 17 is halogens
  • Column 18 is noble gasses 
  • Inner transition metals are columns 3-12
  • Bottom block is outer transition metals
  • Everything under the stairs is other metals
  • All inner transition metals have 2 valence electrons
• • SATP = STANDARD ATMOSPHERIC TEMPERATURE AND PRESSURE