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Flashcards in Organic Chem Class 1 Deck (21)
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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?

1. Assume total gram weight
2. How may moles of x & y are there (# of moles = weight in grams/MW)
3. 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

1. Pauli's Principle - describes carrying capacity of orbital
- no 2 electrons are identical
- limits occupancy of orbital to max of 2 e-

2. 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

3. 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



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



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

Electronegativity increases left to right, bottom to top