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SCH3UE Exam Review (Periodic Trends (Melting point (temp. @ which solid…

- - - - Greater # of electron shells
      - Inner shells block attractive force b/t nucleus and outer e- (shielding)
    - - Greater # of protons/greater nuclear charge
      - More e- e- repulsion (nuclear charge has greater effect)
  - - - Greater nuclear charge (greater attractive pull from nucleus)
      - Greater e- e- repulsion (protons bigger, greater effect than e-)
    - - Greater shells and shielding decreases attractive pull
  - - - Greater nuclear charge (greater pull results in more difficulty to remove e-)
      - After 4 valence e-, atoms prefer to ADD e- to complete shell not remove
    - - More shells/shielding = less attractive pull = less difficult to remove e-
  - - - More protons, greater pull on electrons overall
      - E- e- repulsion
    - - More shells = shielding = less attraction = less likely to hold onto e-
  - - - More nuclear charge decreases of reacting b/c of strong pull on e-
      - E- e- repulsion overridden by nuclear charge
    - - Shielding = greater distance from nucleus/less pull on e- = more likely to react/easier for other atoms to take its valence e-
    - - Fizzing
      - Smoke
      - Heat
      - Light/heat
      - Odor?
    - - More electron shells/shielding = less attractive force to attract oncoming e-
      - More nuclear charge = more attraction due to more protons = outweighed by two other factors
      - More e- e- repulsion to repel oncoming electrons
  - - - More protons down group = more attraction = stronger bonding
      - More shells/shielding = less attraction of outer e- to nuclei
    - - More e- = stronger vdw forces (London dispersion) = more energy needed to separate molecules from each other
    - - Weak intermolecular forces = low mps
      - Decreases from P to Ar due to decreased sizes
- - - - Bond/length increases down group
      - Bond strength decreases down group
    - - Van der Waals' forces (all forces b/t molecules not involving electrostatic attractions)
        
        London dispersion forces - weak attractive forces b/t opp. ends of temp. dipoles (only forces b/t nonpolar molecules, in polar molecules)
        
        Strength increases as size increases (more e- increases probability of temp. dipoles developing)
        
        Boiling point increases as e- increases; low mp/bp b/c little energy required to break forces
        
        Dipole-dipole attraction - force b/t opposing slight charges in permanent dipoles
        
        Mp and bp higher than nonpolar substances
        
        Strength depends on distance/relative orientation
      - Hydrogen bonding (molecule containing H covalently bonded to highly electronegative atom)
        
        Strongest of intermolecular attractions (small size, no other e- to shield)
        
        Bp increases down group (molar mass increases)
        
        Water - each water molecule forms up to 4 H-bonds (ice bonded in tetrahedral arrangement forming open structure less dense than liquid form → water expands when freezes)
      - PHYSICAL PROPERTIES
        
        Melting/boiling points - covalent substances have lower points than ionic compounds (weak forces easier to break)
        
        Macromolecular/giant covalent structures have high points b/c covalent bonds need to be broken for change of state to occur
        
        Solubility
        
        Nonpolar dissolves in nonpolar by formation of London dispersion forces b/t solute and solvent
        
        Polar covalent soluble in water (dipole interactions and H-bond)
        
        Polar compound aqueous solubility decreases where polar bond is only small part of structure
        
        Polar substances have less solubility than nonpolar solvents (dipole-dipole attractions/can't interact well w/ solvent)
        
        Giant substances generally insoluble (too much energy required to break covalent bonds)
        
        Electrical conductivity
        
        Covalent compounds don't contain ions → not conductive
        
        Some polar molecules that can ionize will conduct
        
        Giant covalent molecules are electrical conductors due to mobile e-
  - - - Spectrometer analyses transmitted radiation to produce absorption spectrum
        
        Absorption lines pectrum produced w/ colours of continous spectrum missing
        
        Emission line spectrum: high voltage applied to gas (colors presented are those missing in absorption spectra); can be used as bar code to identify unknown elements
        
        E- cannot change energy continuously/only discretely - energy quantized; spectrum would be continuous if energy not quantized
        
        Hydrogen spectrum **lines converge @ higher energies b/c energy levels closer together → when n=infinite, e- no longer in atom/atom has been ionized - ionization energy
        
        IR radiation when e- falls to third or higher energy level (Paschen series)
        
        Visible light when e- falls to second energy level - Balmer series
        
        UV rays when e- falls to first energy level - Lyman series
  - - - 1 more O = "per" (acid for "ate" = "ic")
      - 1 less O = "ite" (acid = "ous")
      - 2 less O = "hypo" "ite"
      - Partially dissociated acids = change in charge, prefix to show number of H's
    - - Hydro__ acid
    - - Polyatomic __ acid
  - - - Ionic substances - ions (held together by electrostatic attraction b/t cation and anion → lattice structure)
        
        Coordination number: packing of crystals (ions joined by lines that are touching each other)
        
        3D structures
        
        Only conductive in aqueous/liquid b/c free movement of charge required
        
        Ions move to transfer current not e-
      - Molecular substances/crystals - nonpolar or polar molecules
        
        Like dissolves like (charged dissolves charged, vice versa)
      - Network solids - large number of atoms bonded together in crystal for network of covalent bonds
        
        Highly stable
        
        Extremely hard
        
        Poor electrical conductors
        
        Insoluble
        
        Not volatile
      - Metallic solids - e- free to roam
        
        Increase in m/p and b/p as number of e- increases
        
        Not volatile
        
        Malleable (hammered into sheet) and ductile (stretched into wire) b/c metallic bonding is between metal IONS and delocalized e- not actual ions
        
        Bonding not as strong as covalent or ionic
        
        Reacts w/ H2O, insoluble
        
        Dissolves in other metals to form alloys
- - - - Position of e- stated as 3D probability cloud around nucleus
      - Clouds called orbitals
      - Each main energy level has one/several of these clouds depending on how many e- fit in the level
    - - S-orbital: 1 in all main energy levels (n=1,2,3,etc.), spherical centred on nucleus
      - P-orbital: dumbell shaped (two blobs count as one!), 3/main energy level starting @ n=2, each p-orbital oriented along different axis **total 6 e- per level
      - D-orbital: complex shape (double barbell/cloverlea), 5/main energy level starting from n=3 **10 e- per level
      - F-orbital: complex shapes, 7/main energy level starting @ n=4 **holds total 14 e- per level
    - - Orbitals always filled from lowest energy to highest energy (closest to nucleus to furthest away)
      - Put one e- in each orbital of a sublevel then ONLY after whole sublevel is half-filled (go back and double up)
    - - Aufbau Principle: e- always adopt lowest energy configuration by filling one sub-level before starting to fill new level of next higher energy
      - Hund's Rule: sublevels are singly occupied as far as possible (e- prefer PARALLEL spins in separate orbitals) **all orbitals of sublevel will contain one e- before any are filled w/2
      - Pauli Exclusion Principle: no 2 e- can have same 4 quantum numbers (levels, sublevels/orbital types, which orbital, spin), location, spin
    - - Full = (energy level)(orbital: s/p/d/f)^(# e-)
      - Abbreviated: add last noble gas in square brackets
      - **possible for gain/loss of e- to cause ions to have same configuration as another atom/ion
    - - Cr (z=24) → predicted means e- from 4s2 bumped up to 3d4 to become 3d5
      - Cu (z=29) → predicted means e- from 4s2 bumped up to 3d9 to form 3d10
- - - - Translational: energy associated w/ straight line motion
      - Rotational: energy associated w/ rotation of molecules
      - Vibrational: motion of atoms w/in molecules as they move along bond
      - Electronic: e- w/in atom move in relation to nucleus, contribute to KE
    - - Physical - energy used to overcome/allow intermolecular forces to act
      - Chemical - used to overcome electronic structure/chem bonds w/in particles
      - Nuclear - energy used to overcome forces b/t protons and neutrons
      - Energy available in nuclear reaction >> chemical >> physical