1. Atomic structure

What equations can be used to calculate the energy/frequency/wavelength of a photon?

• E=hf

• c=fλ

What is the number of the shell closest to the nucleus?

n=1

What is the electron cloud?

• Region outside the nucleus

• Darker appearance

• Greater probability of finding an electron

What is an orbital?

3D area where an electron is most likely to be found

What are the names of the 3 main electronic configuration rules?

• Pauli exclusion principle

• Hund’s rule

• Aufbau principle

What is the Pauli exclusion principle?

• Maximum of 2 e- per orbital

• e- must have opposing spins

What is Hund’s rule?

e- singly fill a set of degenerate orbitals with parallel spins before doubly occupying with opposing spins

What is the Aufbau principle?

e- fill lowest energy orbitals available

What is the Lewis octet rule?

Atoms tend to gain, share or lose electrons so as to achieve a full, stable octet of valence electrons

Describe what happens to the electrons in an ionic bond

e- transferred

Describe what happens to the electrons in a covalent bond

e- shared

What difference in electronegativity makes a bond more likely to be ionic or more likely to be covalent?

• <1.7 - bond more likely covalent

• >1.7 - bond more likely to be ionic

What electronegativity difference makes a bond polar?

>0.4

In a purely covalent bond, how are the electrons shared between the atoms?

Bonding electrons shared equally between atoms

What happens to the electrons in a purely ionic bond?

e- transferred completely from one atom to the other

Which bonds have a permanent dipole?

• Polar covalent molecule

• Bond/molecule whose ends have opposite charges i.e. δ+, δ-

What is a polar bond?

• An individual covalent bond with uneven distribution of e- density between atoms

• One atom has δ+ charge, other δ-

What is a polar molecule? Include an example

• A molecule with an overall net dipole moment from both polar bonds and an asymmetrical shape (bond polarities cannot cancel out)

• H2O: polar bonds AND polar molecule due to bent structure

How can molecules like CO2 and CCl4 have polar bonds but be non-polar molecules?

• Equal dipole moments point in opposite direction and therefore cancel

• All —> <— or <— —> = non-polar molecule