Organic Chem Class 1 Flashcards
Angstrom
10^-10 m
Limiting Agent
The reactant that runs out first; limits how much product the reaction can produce
How do you determine percent composition by mass?
%x = MW of x/ total MW
How to find a compound’s empirical formula?
- Assume total gram weight
- How may moles of x & y are there (# of moles = weight in grams/MW)
- Find ratio of x & y
Formula for concentration
Molarity (M) = # of moles of solute / # of L of solution
If more than one solute present…
Xs = # of moles of substance s / # of total moles in solution
What happens as the energy levels increase?
- the distance from the nucleus increases
- need more energy to go to higher levels of energy
- gap between the energy levels decrease
- orbital shape is becoming more complex
Excitation vs Relaxation
Excitation is a positive change & electron absorbs incoming photon
Absorption is a negative change & electron emits photon
The energy of the photon is the difference between the initial and final electron energy
Energy of photon equation
E= hf = h (c/λ)
As energy increases, frequency increases too but wavelength decreases
3 Rules for electron filling
- Pauli’s Principle - describes carrying capacity of orbital
- no 2 electrons are identical
- limits occupancy of orbital to max of 2 e- - Aufbau Principle - describes how e- are added or removed from orbitals of different energy
- electrons are added from lowest to highest energy & removed from highest to lowest energy
- valence e- are in highest energy shell
* although 3d electrons are higher in energy than 4s, you remove valence 4s electrons first - Hund’s Rule - describes how e- are added or removed from orbitals of the same energy
- paramagnetic = at least one unpaired e-
- diamagnetic = all e- paired
Metalloids
Possess both metal & non-metal qualities
Boron, silicon, arsenic, antimony, polonium, tellurium, germanium
Which transition metals have anamalous electron configurations?
Gold, silver, copper, chromium, molybdenum
What does the valence shell configuration determine?
Chemical reactivity
Periodic Trend - Acidity
Increases left to right & up to down
- acidity measures compounds ability to lower pH by donating protons or accepting e-
- acidity depends on stability of acid & its conjugate base
- the bigger the anion = the more stable acid = more acidic
Shielding
Valence e- experience an electrostatic attraction due to nucleus given by: Fe ∝ Zeff = C / r^2
Effective Nuclear Charge
Nuclear charge experienced by valence e- given by: Zeff = Z - core e-
Periodic Trend - Atomic Radius
Increases right to left and up to down
- Fe increases and as it increases e- are pulled closer together
Periodic Trend - Ionic Radius
Valence e- repulsion is slightly MORE in anions vs neutral & valence e- repulsion is slightly LESS in cations vs neutral atoms
Periodic Trend - Ionization energy
Minimum amount of energy required to remove outer most e- from atom
IE increases from bottom to top & left to right
Periodic Trend - Multiple ionization
Elements with closed-shell & closed-subshell configuration tend to require more energy to remove an additional electron
Periodic Trend - Electron Affinity
Energy change when adding e- to atom in its gaseous state
Most elements tend to release energy upon addition of e- (exothermic, -)
Elements with closed shell & closed sub-shell require more energy to add e- (endothermic, +)
More negative left to right, bottom to top
Periodic Trend - Electronegativity
Ability of atom to attract e- to itself in a covalent bond
- Metals tend to lose e- in presence of non-metals
FONClBrISCH
Electronegativity increases left to right, bottom to top
