Chemistry Unit Two Quiz

Bohr Model

electrons orbit around nucleus in set energy levels

Quantum Mechanical Model

Electrons are most likely to be found in energy levels, sub levels, and atomic orbitals.

• Sublevel: region in energy level where e- is likely to be found (s,d,p,f)

• Orbital: region in sublevel where e- is likely to be found

S sublevel

First present - n=1

Orbitals - 1

Each orbital can hold 2e-

Total = 2e-

P Sublevel

First Present - n=2

Orbitals - 3

Each orbital can hold 2e-

Total = 6e-

D Sublevel

First present - n=3

Orbitals - 5

Each orbital can hold 2e-

Total = 10e-

F Sublevel

First present - n=4

Orbitals - 7

Total = 14e-

Aufbau Principle

Electrons occupy the lowest energy level, sublevel, and orbital first; like the Bohr Model we must build the electron cloud from the ground up.

Hund’s Rule

When electrons occupy orbitals of equal energy, they don’t pair up until they have to to minimize electron-electron repulsion. Apartment rule —-> single first, then double

Pauli Exclusion Principle

There are two electrons at most per orbital; these electrons must have opposite spins

Valence electrons beyond CA

Assume that electrons with the highest principle quantum number = valence electrons

EXCEPTION: for transition metals, the number of valence electrons can vary depending on which elements are in the chemical bond.

Coulomb’s Law

F = kq1q2/r²

• F = attractive force between two particles

• K = Coulomb’s constant

• q1 and q2 = distance between particles

• R = distance between particles

POGIL

A greater charge (- or +) = a greater attractive force

Less distance = greater attractive force

Core charge calculation

p+ - inner e- = core charge (valence electrons) also Zeff

Shielding

an increase in distance between nucleus and valence electrons that results in a decrease in attractive force

Atomic Radius

The total distance from the atom’s nucleus to the outer boundary of electrons

Less attractive force = bigger atomic radius: when the force is less attractive, it pulls in the electrons less (not as tightly) leading to a bigger atomic radius

First Ionization Energy

The minimum amount of energy needed to remove the most loosely bound outer electron from a neutral atom int he has phase; the amount of energy required to remove the first valence electrons from an atom.

Less attractive force = lower first ionization, more attractive force = higher first ionization

Electronegativity

The ability of an atom to attract outside electrons typically in the context of bonding (NOT amount of energy)

EXCEPTION: Noble gases have no electronegativity because they have full valence energy levels and do not want to attract any more electrons

Less attractive force = lower electronegativity