Ultimate AP Chem Study Guide

Microstate

arrangements (entropy)

Entropy

thermodynamic function that describes the number of arrangements that are available to a system or disorder

enthalpy

thermodynamic quantity that represents the heat content of a system, often measured during constant pressure processes.

first law of thermodynamics

states that energy cannot be created or destroyed, only transformed from one form to another.

the 2nd law of thermodynamics

states that the entropy of an isolated system always increases over time, indicating that natural processes tend to move towards a state of disorder.

the third law of thermodynamics

states that as the temperature of a system approaches absolute zero, the entropy approaches a constant minimum.

greater # of arrangements/microstates

leads to higher entropy in a system

atomic radius increases

down a group due to increase in outer shells, to the left due to a decrease in protons/nuclear charge

ionization energy, electron infinity, and electronegativity increases

up a group due to increase in nuclear charge, towards the right due to an increase in protons

why are there exceptions to ionization energy?

when electrons are removed, some atoms gain a special stability while other elements lose that special stability

orbital

region of probability of where electrons can be found, each one can hold 2 electrons

exceptions to filling order for orbitals

Cr ([Ar] 4s1. 3d5), Cu (4s1, 3d10)

aufbau principle

electrons occupy the lowest energy orbitals first before filling higher energy levels

pauli exclusion princple

two electrons cannot have the same spin

hund’s rule

electron will always occupy an empty orbital first

relationship between ionization and kinetic energy

once the minimum standard of energy is met to remove electrons (IE), the rest becomes kinetic energy

NO₃⁻

Nitrate

NO₂⁻

Nitrite

SO₄²⁻

Sulfate

SO₃²⁻

Sulfite

PO₄³⁻

Phosphate

CO₃²⁻

Carbonate

HCO₃⁻

Bicarbonate

C₂H₃O₂⁻ / CH₃COO⁻

Acetate

OH⁻

Hydroxide

NH₄⁺

Ammonium

MnO₄⁻

Permanganate

CrO₄²⁻

Chromate

Cr₂O₇²⁻

Dichromate

All nitrates (NO₃⁻), acetates (C₂H₃O₂⁻), and alkali metals are

**soluble**

Most chlorides, bromides, iodides are

soluble **except Ag⁺, Pb²⁺, Hg₂²⁺**

Most sulfates are

soluble **except Ba²⁺, Sr²⁺, Pb²⁺**

Most hydroxides are

**insoluble** except Group 1, Ba²⁺, Sr²

Most carbonates and phosphates

are **insoluble** except Group 1 and NH₄⁺

Atomic Radius

Increases down, decreases across

Ionization Energy

Decreases down, increases across

Electronegativity

Decreases down, increases across

Electron Affinity

Becomes more negative across a period

name the strong acids

HCl, HBr, HI, HNO₃, H₂SO₄, HClO₄

**Strong Bases**

NaOH, KOH, Ba(OH)₂, Ca(OH)₂, Sr(OH)₂

**Oxidation**

occurs at the **anode**

**Reduction**

occurs at the **cathode**

Electrons flow from

**anode to cathode**

Favorable reaction

**E°cell > 0**

conversion for atm

1 atm = 760 mmHg = 101.3 kPa

formal charge

valence electrons - (bond +dots)

lewis dot strcutures: hydrogen only requires

2 electrons

lewis dot strcutures: beryllium only requires

4 electrons

lewis dot strcutures: boron only requires

6 electrons

common expanded octets

PCl5, SF4 (two dots) , XeF4 (4 dots)

linear

180 degrees, sp

three groups of electrons

sp2, 120, trigonal planar, bent (1 lone pair)

4 groups of electrons

4 groups, 109.5, sp3, tetrahedral, trigonal pyramidal (1 lone pair), bent 105 (2 lone pairs)

5 groups of electrons

trigonal bipyramidal, seesaw (1), t-shaped (2), linear (3)

6 pairs of electrons

octahedral, 90, square pyramidal (1), square planar (2)

smaller the formal charge

the better, more stable the molecule or ion is. Lower formal charges on atoms indicate a more favorable electron distribution.

what bonds can conduct electricity

ionic compounds (in solution), metallic

for interstital allou when atoms are _____ sized different

greatly, atoms combine easier