2.5 Electrons, Bonding and Structure Flashcards
What is the principal quantum number ?
Number representing the overall energy of each orbital, which increases with distance from the nucleus.
What is the main energy level ?
Also known as the shell. It is a group of atomic orbitals with the same principal quantum number.
What is an atomic orbital ?
Volume of space that can contain up to 2 electrons of the opposite spin.
How many electrons can occupy the first energy level ?
2 electrons maximum.
How many electrons can occupy the second energy shell ?
18 electrons maximum.
How many electrons can occupy the 4th energy level ?
32 electrons maximum.
How many electrons can occupy the 5th energy level ?
50 electrons maximum.
What are s-orbitals ?
S-orbitals are spherical around the nucleus of an atom. They can contain 2 electrons maximum. Each energy level has an s-orbitals.
What are p-orbitals ?
P-orbitals are a dumb-bell shape with the nucleus in the middle. Can contain 6 electrons maximum. There are no p orbitals in the first energy level.
What are d orbitals ?
D-orbitals occupy a flower shape around the nucleus. Can contain 10 electrons maximum (5[] x2).
What sub-shell has the lowest energy ?
1s has the lowest energy and therefore, gets filled first.
What do opposite spins help to do ?
Help to counteract repulsion between negative charges of 2 electrons. 2 electrons in an orbital must have opposite spins.
What do blocks in periodic table correspond to ?
Blocks correspond to their highest sub-shell energy.
What is the s-block ?
S-blocks highest energy electrons are in the s-sub shell (left block of the 2 groups).
What is the p-block ?
P-blocks highest energy electrons are in the p-sub shell (right block of the 6 groups).
What is the d-block ?
D-blocks highest energy electrons are in the d-sub shell (centre block of the 10 groups).
When forming ions, what do the highest energy sub-shells do ?
When forming ions, the highest energy sub-shells lose or gain electrons in the s-block or p-block orbitals.
What happens to d-block when forming ions ?
For d-block elements, the 4s sub-shell is at a lower energy than the 3d sub shell, so is filled first. The energies of the two are close together and once filled the 3d sub-shell falls below the 4s sub-shell.
What is ionic bonding ?
Electrostatic attraction between positive and negative ions in ionic compounds.
What do the simplest ionic compounds contain ?
Simplest ionic compounds contain metal and non-metal ions.
What is the structure of ionic compounds ?
Each ions attract oppositely charged ions in all directions. This results in a giant ionic lattice containing billions of ions.
What can the physical properties be explained by ?
Physical properties can be explained by lattice structure and ionic bonding.
What is the melting and boiling point of ionic compounds ?
Almost all ionic compounds are solid at room temperature, as there is insufficient energy to overcome the strong electrostatic attraction between oppositely charged ions in a lattice.
What is the solubility of ionic compound ?
Many ionic compounds dissolve in polar solvents, such as water. Polar water molecules break down the lattice and surround each ion in the solution.
What is the solubility in compounds of ions with a large charge ?
In compounds with ions of a large charge, the ionic attraction may be too strong for polar solvents to break down the lattice structure. The compound will then not be very soluble.
Can ionic compounds conduct electricity in a solid state ?
In a solid state, an ionic compound does not conduct electricity.
Can ionic compounds conduct electricity melted or dissolved in water ?
Yes, ionic compounds can conduct electricity in a liquid sate or aqueous solution.
Structure of ionic lattice in a solid state
-Ions are in a fixed position.
-No mobile charge carriers.
-No conductivity.
-Cannot move.
Structure of ionic lattice in dissolved state
-Solid lactic breaks down.
-Ions are free to move.
-Can conduct electricity.
What is covalent bonding ?
Strong electrostatic attraction between a shared pair of electrons and the nuclei of the bonded atoms.
What is an orbital overlap ?
Covalent bonding is the overlap of atomic orbitals forming a sigma bond.
What does it mean when the attraction is localised and what does it result in ?
Attraction is localised, solely between the shared pair of electrons and the nuclei of 2 bonded atoms. Results in a molecule, which is the smallest part of a covalent bond that still retains properties of a covalent compound.
What are dot and cross diagrams ?
Show the sharing of electrons from different atoms and electrons min the outer shell of an atom.
When do multiple covalent bonds exist ?
Exist when atoms share more than one pair of electrons between atoms. Double covalent bond is the sharing of 2 pairs of electrons. Triple covalent bond is the sharing between 3 pairs of electrons.
Why does boron form an unusual covalent bond ?
BF3 has three electrons in outer shell and shares all 3, meaning only has 6 electrons total in the outer shell. This shows that predictions for bonding cannot base solely on noble gas electron structure.
Why does sulfur form an unusual covalent bond ?
SF4 has 4 electrons in sulfur that bond to 4 fluorine leaving a lone pair of electrons. This means sulfer has 10 electrons in the outer shell.
What is a dative covalent bond ?
Shared pair of electrons, where both electrons come from the same atom.
