Week 3 - Periodic Table and Properties Flashcards
What are the four quantum numbers?
- Principal (n)
- Angular (l)
- Magnetic (ml)
- Spin (ms)
What can the values of ms be?
-1/2 or 1/2
What do each of the four quantum numbers tell us about the orbital/electron?
n: size of orbital
l: shape of orbital
ml: orientation of orbital
ms: direction of electron momentum
Electrons possess what kind of momentum?
Angular (similar to a spinning object)
No two electrons can have the same…
four quantum numbers
An orbital can have how many electrons?
Max. 2
If the nuclear charge is higher, the electron is _____ to remove.
Harder
Equation to calculate effective nuclear charge?
Zeff = Z - S
Z is atomic number
S is shielding value
Explain what electron shielding is.
Inner electrons ‘shield’ outer electrons from the charge of the nucleus; if electrons are in the same shell they shield one another a small amount and make the electrons easier to remove.
Why do 1s electrons shield 2p electrons?
2p orbital is farther from the nucleus than 1s orbital. (note that they do not FULLY shield them)
L value trend for penetrating power of electrons in the same shell
s > p > d ≈ f
Order of atomic orbitals from lowest to highest energy
1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s, 4d, 5p, 6s, 4f
Afbau Principle
Build up the periodic table (or atoms) by adding one proton at a time to the nucleus and one electron around the nucleus to get the ground state electronic configuration. The electrons sequentially fill the lowest energy orbital available.
Describe where the s, p, and d orbitals fall on the periodic table
S is left block (and He)
P is right block
D is middle block
Orbitals are more stable when they are…
half-filled or fully filled
How to determine valence electrons from electronic configuration?
For main group: electrons in highest n are valence
For transition group: (n)s electrons and (n-1)d electrons are valence
Number of valence electrons in periodic table
In main group elements, it increases from 1 to 8
Isoelectronic
Same number of electrons
Atomic radius is largest where on the periodic table (main group elements)?
Bottom left
Ionization energy
The energy required for the complete removal of 1 mol of electrons from 1 mol of gaseous atoms or ions
formula for ionization energy (IE); in the same element which IE is larger?
atom (g) → ion+ (g) + e-; IE1 < IE2 < IE3…
Where on the periodic table is ionization energy highest?
top right
Which elements are the exceptions of the ionization energy trend? Why?
B and Al; they have the first np electrons.
O and S; have a fourth np electron
Electron Affinity
The energy change that accompanies the addition of 1 mol of electrons to 1 mol of gaseous atoms or ions
Formula for electron affinity
atom (g) + e- → ion- (g) ; ∆E= EA
Which elements have high electron affinity?
Halides (second last column)
Electronegativity
Ability of an atom in a bond to attract electron density toward itself
Atoms that have a high electron affinity…
tend to be very electronegative
Where on the periodic table is metallic character the highest?
Bottom left
When removing electrons to make a cation, which electrons are removed first?
Highest n; eg. 4s is removed before 3d and so on
Paramagnetism vs diamagnetism
Para = contains one or more unpaired electron
Dia = only has paired electrons
What happens to ionic size and Zeff when an atom ionizes into a cation?
Size decreases, Zeff increases
What happens to ionic size when an atom ionizes into a anion?
Size increases, more e-e repulsion
In comparing isoelectronic cations and anions, the ____ will have a larger size.
Anion
