Chem regents tips

• Elections


  Both a partide & a ware
• Weighting Average atomic mass of an element

  NATURALLY OCCULARING
• Compounds


  Mixed in a molecular level
• Boso


  Always going to be HOMOGENEOUS MIXTURE
• Mixtures


  • Their compositions & raties may vary
• Water CH₂O is a pure substance
• Air is a mixture of different partides
• If compositions vary substances worst be of the same material
• Planetary Model


  Pictures atoms we traveling in circular bruits
• Sequence of Atomic History

  1. Atom-hard spare

  2. Atuon is empty space

  3. In orbitals
• Nucleus of an atom


  Swilller than nucleus & contains most of atown's mass
• Atten in excited state

  Has more potential energy than atton in ground more
• LOOK OUT FOR KEYWORDS
• It same # of Ple, charge on particle is neutral
• Neutral atoms have equal # of protons I electrons
• To look for a element using a Lewis Dot Diagram


  Look at eat shells
• Solution


  Mixture of substances
• Bright Line Spectra forms

  Elections emit light energy, going from exited state to ground state
• On the regents, linear sympol for excited state configuration incans turn ground state & configuration to excited state (che normal
• If theres a number in front of a compound, that's how many atoms each element in the compound has. Ex. 6A₂0 boys
• When there's a roman numeral in front of a metal in a comprend and you're asked to write the formula, switch the numeral to the non-metal and give the original suboccipt from the periodic table to the metal. (Cancel out subscripts if needed)
• Heavier ble gases like Kr. Krypton, can form compounds with highly reactive elements like F, florive
• When asked the net amount of energy released & abroad when one mole of smrth is produced, find the given egnation on Table I and look at the AH (h]) #
• The Bp of t₂O is 100°C & the freezing point is o°C
• Mass of an object & the average hinetic energy

  Have a direct relationships
• When doing a MCAT, you have to use joucles, not kilojoules. To convert, I hilaule (15) is 1000 Joules (3)
• The only group in the Periodic Table that has elements in all states of matter is the halogens (Group 1)
• Elements in a group have similar chanical props. b/c they have the same mimber of valence elections
• Ion is always a solid at room temp pressure
• CF are always gas at rm, temp, I pressure
• When they say # of innermost e-,, ust add up the e in the element's e- configuration, excluding the last #as it's the # of valence e
• Metals have mobile ions, so they're good conductors of mig
• When they ask the name & change of a particle thats gained/lost, it's always going to be election, having a negative charge
• Only the noble gases are monety mic at m. Tema & presence, no other gas b/c they're stable
• Elements found naturally only in compounds are pres
• Energy released when a system loses energy (exo) & bonds are formed, the stability of the system increases
• W₂


  Has a linear structure ŏ==Ö
• Metal atoms w/ metallic bonding occuring has vocant valence e- & low ionization energie's
• In diagrams, molecules have to be bonded / connected together
• Forces but. atoms that create chemical bonds are the result of the interactions but protons & e-