Summary Notes - Chapter 1: Atomic Structure

‭Atomic‬‭Structure‬



‭-‬ E
‭ lectrons‬‭are‬‭arranged‬
‭in‬‭shells‬‭(energy‬
‭levels).‬




‭ elative‬‭Atomic‬‭Mass‬‭is‬
R
‭different‬‭to‬‭mass‬‭number.‬‭RAM‬‭is‬‭weighted‬‭average‬‭of‬‭isotopes‬‭included.‬
‭RAM‬‭=‬‭ratio‬‭of‬‭average‬‭mass‬‭of‬‭atoms‬‭of‬‭an‬‭element‬‭on‬‭a‬‭scale‬‭where‬‭1‬‭atom‬‭of‬
‭carbon‬‭is‬‭exactly‬‭12‬


-‭ ‬ T ‭ he‬‭shells‬‭have‬‭sub-shells‬‭(sub-levels).‬
‭-‬ ‭Each‬‭shell‬‭/‬‭subshell‬‭is‬‭made‬‭up‬‭of‬‭electron‬‭orbitals‬
‭which‬‭can‬‭each‬‭hold‬‭2‬‭electrons.‬
‭-‬ ‭The‬‭two‬‭electrons‬‭in‬‭each‬‭orbital‬‭spin‬‭in‬‭opposite‬
‭directions‬
‭-‬ ‭Orbitals‬‭are‬‭regions‬‭of‬‭space‬‭that‬‭electrons‬‭are‬
‭likely‬‭to‬‭be‬‭in‬
‭-‬ ‭Eg‬‭first‬‭shell‬‭has‬‭one‬‭sub‬‭shell‬‭which‬‭has‬‭2‬
‭electrons.‬
‭-‬ ‭4‬‭sub‬‭shells‬‭in‬‭second‬‭to‬‭hold‬‭8‬‭electrons‬
‭-‬ ‭Formula‬‭for‬‭calculating‬‭how‬‭many‬‭electrons‬‭in‬‭a‬
‭shell‬‭is‬‭2n‬‭2‬‭where‬‭n‬‭is‬‭the‬‭shell‬‭number‬‭(2nd‬‭shell)‬
‭-‬ ‭s‬‭orbital‬‭is‬‭spherical,‬‭p‬‭orbital‬‭is‬‭cylindrical-ish‬
‭(px,py,pz‬‭(axis))‬

, ‭ rbitals‬‭are‬‭in‬‭SUBSHELLS‬‭which‬‭are‬‭in‬‭SHELLS‬
O
‭Each‬‭ORBITAL‬‭can‬‭have‬‭2‬‭electrons‬

‭ hell‬‭2‬‭-‬‭has‬‭one‬‭x‬‭s‬
S
‭orbital‬‭and‬‭three‬‭x‬‭p‬
‭orbitals‬


‭ LWAYS‬‭FILL‬
A
‭ELECTRONS‬‭FROM‬
‭LOWEST‬‭IN‬
‭ENERGY‬

‭ ach‬‭orbital‬‭can‬‭hold‬
E
‭2‬‭electrons‬

‭ ach‬‭has‬‭a‬‭different‬
E
‭spin‬‭on‬‭it‬‭-‬‭quantum‬
‭mechanics.‬

‭ o‬‭1s‬‭can‬‭have‬‭2‬
S
‭electrons,‬‭one‬
‭pointing‬‭up,‬‭one‬
‭down.‬

‭Fill‬‭up‬‭first‬‭available‬‭space.‬

‭ hromium‬‭+‬‭Copper‬‭-‬‭anomalies.‬‭4s‬‭only‬‭takes‬‭one‬‭electron‬‭instead‬‭of‬‭2‬‭-‬‭extra‬‭one‬
C
‭goes‬‭to‬‭3d.‬

‭ ufbau‬‭Principle‬‭-‬‭electrons‬‭enter‬‭lowest‬‭energy‬‭level‬‭available‬
A
‭Hund’s‬‭Rule‬‭-‬‭Electrons‬‭prefer‬‭to‬‭occupy‬‭orbitals‬‭on‬‭their‬‭own,‬‭and‬‭only‬‭pair‬‭up‬‭when‬‭no‬
‭empty‬‭orbitals‬‭of‬‭the‬‭same‬‭energy‬‭are‬‭available.‬


‭ ighest‬‭energy‬‭electrons‬‭are‬‭lost‬‭when‬‭an‬‭ION‬‭is‬‭formed.‬‭4s‬‭electrons‬‭lost‬‭before‬‭3d‬
H
‭(once‬‭occupied,‬‭4s‬‭moves‬‭above‬‭3d)‬