Chapter 5: Electrons and bonding Flashcards
Electron structure, ionic bonding, covalent bonding.
What are electron shells?
Shells can be regarded as energy levels for electrons where energy increases in accordance to a shells principle quantum number.
What are orbitals?
Regions around a nucleus where a pair of electrons with alternate spins are likely to reside.
How many electrons can be held in an orbital?
2 of alternate spin
What are the 4 key types of orbital
S, P, D & F
What is the S- orbital?
A spherical region around the nucleus; present at all energy levels, 1 per level.
What is the P- Orbital?
A dumbbell shaped region; present at energy level 2 and up, 3 per level in the X, Y, Z plane.
What is the D- orbital?
A dumbbell shaped region; present at energy level 3 and up, 5 per level
What is the F- orbital?
A dumbbell shaped region; present at energy level 4 and up, 7 per level in the X, Y, Z plane.
What is the maximum number of electrons in shell 1?
2
What is the maximum number of electrons in shell 2?
8
What is the maximum number of electrons in shell 3?
18
What is the maximum number of electrons in shell 4?
32
What are the maximum number of electrons in each subshell?
S-2, P-6, D-10, F-14
When will electrons pair?
When all other orbitals in that subshell have at least one electron in them.
Electron orbital fill order at high energy levels
1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 4d, 4f
How do you notate electron configuration?
Energy level, subshell, number of electrons:
1s²2s²2p³ (N)
What the shorthand for electron configuration?
Next lowest noble gas and then state all used higher energy subshells:
[Ar] 3d²4s² (Ti)
How do lose of electrons in d-block ions differ from elsewhere?
D orbital of the lower quantum energy level will empty before and fill after the S orbital of the higher energy level.
Properties of ionic compounds.
High melting point due to electrostatic attraction in their crystal structure. Soluble in polar solvents due to break down of the crystal lattice when solvent molecules surround an ion. Only conductive in solution.
What is covalent bonding?
The strong electrostatic attraction of nuclei to a shared pair of electrons. producing a localised attraction to form a molecule.
What is a σ-bond?
A covalent bond from the direct overlap of orbitals.
What is a π-bond?
A covalent bond from the lateral joining of orbitals above and below the bonding plane.
What is a double covalent bond?
A bond containing a π-bond and a σ-bond involving 4 electrons.
What is a single covalent bond?
A σ-bond involving 2 electrons.
What is a triple covalent bond?
A bond involving 6 electrons.
What is a dative or co-ordinate bond?
A covalent bond where a shared pair of electrons has been donated by a single atom from the bonding atoms.
What is bond enthalpy?
The energy stored in a bond. It is the amount released when it is formed and the amount required to break it.
