Module 2.2 Electrons, Bonding and Structure Flashcards
The principle quantum number, n, indicates
The shell that the electrons occupy
The larger the value of n,
The further the shell is from the nucleus and the higher the energy level
Number of electrons in the first shell
2
Number of electrons in the second shell
8
Number of electrons in the third shell
18
Number of electrons in the fourth shell
32
An orbital can
Hold a max. of 2 electrons with opposite spins
An orbital is a region of space where electrons are most likely to be found
4 different types of orbital
s
p
d
f
S orbitals
Spherical shape
Can hold 2 electrons
P orbitals
3D dumbbell shape
Can hold 6 electrons
Electron energy levels
1s
2s
2p
3s
3p
4s
3d
4p
4d
4f
Filling shells and sub-shells rules
The lowest energy level is filled first
Each energy level must be full before the next higher energy level starts to fill
Each orbital is filled singly before pairing starts
The 4s orbital is at a slightly lower energy level than the 3d orbital. Therefore, 4s fills before 3d
Electron configuration of ions
Electrons in the highest energy levels are lost first
Ionic bonding
Metal + non-metal
Electrons are transferred from the metal atom to the non-metal atom
Oppositely charged ions formed that attract each other
Covalent bonding
Two non-metals
Electrons are shared between the atoms and are attracted to the nuclei of both bonded atoms
Metallic bonding
Occurs in metals
Electrons are shared between all atoms
Ionic bonds
Electrons are transferred from the metal atom to the non-metal atom
Oppositely charged ions form, which are bonded together by electrostatic attraction
The metal ion is positive (cation)
The non-metal ion is negative (anion)
Giant ionic lattices
Each ion is surrounded by oppositely charged ions
These ions attract each other from all directions, forming a 3D giant ionic lattice
All ionic compounds exist as giant ionic lattices in the solid state but when aqueous, the ions are free to move so they can conduct when aqueous or molten
Ionic compound properties: high melting and boiling points
Ionic compounds are solids at room temperature- a large amount of energy is needed to break the strong electrostatic bonds that hold the oppositely charged ions together in the lattice. Therefore, ionic compounds have high melting and boiling points.
The greater the charge, the stronger the electrostatic forces between the ions so more energy is required to break up the ionic lattice during melting
Ionic compounds: Electrical conductivity
In a solid ionic lattice:
The ions can’t move - can’t conduct
When aqueous or molten:
The solid lattice breaks down - the ions are free to move
Can conduct