Electronic Structure Flashcards
What is the number given to each shell called?
Principal quantum number
What can be said about the energy and principal quantum number when a shell gets further away from the nucleus?
The higher it’s energy and the larger it’s principal quantum number is
What are shells divided into?
Sub-shells
What are the 4 types of sub-shell?
S
P
D
F
What is an orbital?
A region of a sub-shell that contains a maximum of 2 electrons with opposite spins
What is spin?
A type of momentum possessed by an electron which can either be up or down
How many electrons can s sub-shells hold?
2
How many electrons can p sub-shells hold?
6
How many electrons can d sub-shells hold?
10
How many electrons can f sub-shells hold?
14
What can be said about the energy of orbitals in the same sub-shell?
They have the same energy
What is spin-pairing?
When there are 2 electrons in an orbital which spin in opposite directions
What shape are s-orbitals?
Spherical
What shape are p-orbitals?
Dumbbell shape
What is the formula for the number of electrons a shell can hold?
2n^2 (n being shell number)
What is electron configuration?
The number of electrons and how they’re arranged
Why do 4s sub-shells fill first before 3d sub-shells?
4s sub-shells have a lower energy level
What did Werner Heisenberg came up with?
The theory that you cannot know the speed of an electron or it’s exact position
What was Heisenberg’s theory called?
Uncertainty principle
How do ions form?
When atoms lose or gain electrons to become positively or negatively charged
What is electrostatic attraction?
A strong force between positive and negative ions
What is an ionic bond?
An electrostatic attraction between 2 oppositely charged ions
What is an ionic compound?
When oppositely charged ions form an ionic bond
What are ionic crystals?
Giant lattice (regular structure) of ions
How does a lattice form?
When each ion is electrostatically attracted in all directions to ions of the opposite charge
Describe the electrical conductivity of ionic compounds
Conduct electricity when molten or dissolved, but not when solid
Why do ionic compounds not conduct electricity when solid?
There are no mobile ions as they’re fixed in position by strong metallic bonds
Why do ionic compounds conduct electricity when molten or dissolved?
They have ions that are free to move (mobile ions) so can carry charge
Describe the melting and boiling points of ionic compounds?
Have high melting and boiling points
Why do ionic compounds have high melting and boiling points?
The giant ionic lattices are held together by strong electrostatic forces (which takes lots of energy to overcome)
Describe the solubility of ionic compounds
Tend to dissolve in water
Why do ionic compounds tend to dissolve in water?
Water molecules are polar, so the water molecules pull the ions away from the lattice and cause it to dissolve
What does polar molecule mean?
Part of the molecule has a negative charge, the other bits have a positive charge
How are molecules formed?
When 2 or more atoms bond together
What are molecules held together by?
Strong covalent bonds
What is a covalent bond?
The strong electrostatic attraction between a shared pair of electrons and the nuclei of the bonded atoms
Give an example of a molecule with triple bonds
Nitrogen (N2)
Give an example of a molecule with double bonds
Oxygen (O2)
What is different between a single covalent bond and a dative covalent bond?
In a single covalent bond, atoms share electrons with the electrons coming from each atom. Dative covalent bonds shares electrons but both electrons come from the same atom
How can you show a dative bond on a diagram?
By an arrow, pointing away from the donor atom
What is different about boron trifluoride?
The boron only has 6 electrons on its outer shell
What does expanding the octet mean?
Having an outer shell with more than 8 electrons
Give an example of a molecule that expands the octet
Sulfur Hexafluoride, has 12 electrons in it’s outer shell
What does enthalpy mean?
Another word for energy
What does the average bond enthalpy tell you?
The strength of a covalent bond
What does average bond enthalpy measure?
The average energy needed to break a bond
What does the shape of a molecule depend on?
The number of pairs of electrons in the outer shell of the central atom
What are shared electrons called?
Bonding pairs
What are unshared electrons called?
Lone pairs