CHAPTER 5: ELECTRONS AND BONDING Flashcards
What is the shell number called?
The principal quantum number
What is an atomic orbital?
A region around the nucleus that can hold up to two electrons, with opposite spins.
How many electrons can orbitals hold?
2
What is the shape of an s-orbital?
A sphere
What is the shape of an p-orbital?
A dumbell
What is the electronic configuration of zinc?
1s2 2s2 2p6 3s2 3p6 4s2 3d10
What is ionic bonding?
Electrostatic bonding between positive and negative ions.
What does ionic bonding form?
A giant ionic lattice as ions attract oppositely charged ions in all directions
Why do ions have high melting and boiling points?
High temperatures are needed to provide the large quantity of energy needed to overcome the strong electrostatic attraction between the ions. The melting points are higher for lattices containing ions with greater ionic charges, as there is stronger attraction between ions. Ionic attraction also depends on the size of the ions.
Are ionic bonds soluble?
Many ionic compounds dissolve in polar solvents. In a compound made of ions with large charges, the ionic attraction may be too strong for water to be able to break down the lattice structure.
Solubility requires two main processes:
the ionic lattice must be broken down, and water molecules must attract and surround the ions. The solubility of an ionic compound in water therefore depends on the relative strengths of the attractions within the giant ionic lattice and the attractions between ions and water molecules.
Can ionic bond conduct electricity?
In the solid state: the ions are in a fixed position in the giant ionic lattice so there are no mobile charge carriers. An ionic compound is a non-conductor of electricity in the solid state.
When liquid or dissolved in water: the solid ionic lattice breaks down the ions are now free to move as mobile charge carriers. An ionic compound is a conductor of electricity in liquid and
aqueous states.
What is covalent bonding?
Strong electrostatic attraction between a shared pair of electrons and the nuclei of the bonded atoms.
What does a covalent bond create?
A molecule
What is a dative covalent bond?
A covalent bond in which the shared pair of electrons has been supplied by one of the bonding atoms only.
What does average bond enthalpy measure?
The strength of a covalent bond
What is a shell?
A group of orbitals with the same principal quantum number
What are the rules by which electrons are arranged in the shell?
● Electrons are added one at a time
● Lowest available energy level is filled first
● Each energy level must be filled before the next one can fill
● Each orbital is filled singly before pairing
● 4s is filled before 3d
Why does 4s orbital fill before 3d orbital?
4s orbital has a lower energy than 3d before it is filled
Which electrons are lost when an atom becomes a positive ion?
Electrons in the highest energy levels
Define metallic bonding
Electrostatic attraction between the positive metal ions and the sea of delocalised electrons
How many covalent bonds does carbon form?
4
How many covalent bonds does oxygen form?
2
What is a lone pair?
Electrons in the outer shell that are not involved in the bonding
What does expansion of the octet mean?
When a bonded atom has more than 8 electrons in the outer shell
What are the types of covalent structure?
● Simple molecular lattice
● Giant covalent lattice
Give examples of giant covalent structures
● Diamond
● Graphite
● Silicon dioxide, SiO 2
