periodic properties

Question 1

what is Zeff

Answer 1

the amount of positive charge (nuclear charge) experienced by an electron

• inner electrons prevent outer electrons from “feeling” the positive charged center, this explains why valence electrons are easier removed

Zeff = Z - s
where:
Z = # protons (atomic number)
s = # of shielding (non-valence) electrons

Question 2

Atomic radius and bond length relationship

Answer 2

Atomic radius = 1/2 bond length of atoms (distance between two atoms)

“smallest atom” = smallest atomic radius

Question 3

What is electron affinity?

Answer 3

the amount of energy released when an e- is added to an atom

Question 4

Most transition metals form colored complexes, EXCEPT:

Answer 4

row 4 transition metals are an exception to this rule and appear colorless.

Question 5

What are the properties of transition metals?

Answer 5

• High melting and boiling point
• Good conductors of heat and electricity
• Hard, tough, and has high density
• Form colored-compounds (exception: row 4)
• Multiple oxidation states
• Many are used as catalysts

Question 6

What are the most prominent oxidation states for transition metals and inner transition metals

Answer 6

Transition metals: 2+

Inner-transition metals (lathanides and actinides): 3+

Question 7

Metals properties

Answer 7

• Malleable and lustrous
• Form basic oxides
• High melting and boiling points
• Lose electrons to form cations
• Good conductors of electricity
• Solid at room temperature (exception: mercury)

Question 8

Non-metals properties

Answer 8

• Brittle and dull
• Form acidic oxides
• Low melting and boiling points
• Gain electrons to form anions
• Poor conductors of electricity and heat
• Gas or solid at room temperature (exception: bromine)

Question 9

What is the mass number and atomic number equal to?

Answer 9

atomic number = # protons

mass number = #protons + #neutrons

Question 10

What are all the quantum numbers and what do they define?

Answer 10

1. Principal quantum number (n):
   - main energy level/shell occupied by an e-
   - eg 1,2,3… (positive integer > 0)
   - max # of e- in each energy level = 2n^2
2. Azimuthal quantum number (l):
   - shape of orbitals/subshells
   - between 0 and (n-1)
3. Magnetic quantum number (ml):
   - orientation of orbitals in space
   - between +l and -l
4. Spin quantum number (ms)
   - angular momentum of an e-
   - +1/2 or -1/2 (upwards or downwards spin)
   - two e-‘s in the same orbital MUST have OPPOSITE spins (antiparallel)

Question 11

What is Pauli’s Exclusion Principle?

Answer 11

no two e- within an atom can have the exact same quantum #

Question 12

Formal charge equation

Answer 12

Formal charge = (# valence e-) - (# non bonding e-) - (# of bonds)

Question 13

Bond order equation

Answer 13

Bond order = [(# e- in bonding orbitals) - (# e- in antibonding orbitals)] /2