Chapter 5: Electron and bonding (5.1-5.3) Flashcards
What are the maximum number of electrons in the first four shells?
1st shell = 2, 2nd shell= 8, 3rd shell = 18, 4th shell = 32 (Use the formula 2n^2 to find the maximum number of electrons)
What are the four types of atomic orbitals?
s-, p-, d-, f-
Shape of an s- orbital?
- It has a spherical shape (draw a circle)
Shape of a p-orbital?
- It has a shape like a bar bell
what shells contain d-orbitals?
Each shell from n = 3 contains 5 d-orbitals
Maximum number of electrons in orbitals s-, p-, d-, f-
S = 2, P = 6, D = 10
What are the two rules of how electrons fill sub-shells?
- Electrons in the same sub-shell fill up orbitals singly before pairing
- Orbitals fill in order of increasing energy (e.g in the n = 2 shell the order is 2s, 2p)
What is the anomaly of how electrons fill sub-shells and how does this effect how you write electronic configurations of elements and ions?
The 3d sub-shell is at a higher energy than the 4s sub-shell. This means that the 4s sub shell fills before the 3d sub shell and also loses electrons before the 3d sub-shell, therefore the order of filling is 3p, 4s, 3d.
Why does the 4s shell also lose electrons before the 3d sub-shell?
The energies of the 4s and 3d sub-shells are very close together. Once filled the 3d energy level falls below the 4s.
How do you classify elements into different blocks?
Their blocks corresponds to their highest energy sub-shell meaning there can be 4 blocks (s, p, d, f)
What is ionic bonding?
What structure is formed in ionic compounds?
The electrostatic force of attraction between positive and negative ions
Giant ionic lattice
Melting and boiling point of ionic substances
High temperatures are required to supply the energy needed to overcome the strong electrostatic force of attraction. Therefore ionic compounds have high melting points.
What does the melting point in ionic lattices depend on?
Melting points are higher for lattices containing ions with greater ionic charges and ionic attraction also depends on the size of the ions.
Solubility of ionic compounds
They dissolve in polar solvents (e.g water) as these break down the lattice and surround each ion in solution.
What does the solubility of ionic compounds depend on?
The charges in the lattice - they may be too strong for water to break down the lattice. Therefore it depends on the attraction between ions and water molecules and the relative strength of attraction within the lattice.
Electrical conductivity of ionic compounds
In solid state ionic compounds do not conduct electricity because the ions are in fixed positions in the giant ionic lattice and there are no mobile charge carriers. However ions are mobile in liquid state.
What is covalent bonding?
The strong electrostatic force of attraction between a shared pair of electrons and the nuclei of the bonded atoms.
How is an ionic bond different to a covalent bond ?
Ionic bonding is the loss and gain of electrons whereas a covalent bond is sharing electrons.
What can chlorine do due to it having 7 unpaired electrons?
It could form ClF7 meaning that the outer shell would have 14 electrons and chlorine’s n=3 shell can hold 18 electrons
What is a dative covalent (coordinate) bond?
A shared pair of electrons in which the bonded pair has been supplied by one atom only (e.g. NH4)
What is a simple molecular lattice?
Its where molecules are held in place by weak intermolecular forces but the atoms within each molecule are bonded together strongly by covalent bonds.
Why do simple molecular substances have low melting and boiling points?
The weak intermolecular forces of attraction (London forces) do not take much energy to overcome and the covalent bonds do not need to be broken.
Describe electrical conductivity in simple molecular substances
There are no mobile charged particles in simple molecular structures, with no charged particles that can move, they cannot conduct electricity
strength of multiple covalent bonds
more covalent bonds = stronger
types of covalent structure
simple molecular
giant covalent lattice
graphene
define electronegativity
A measure of the attraction of a bonded atom for the pair of electrons in a covalent bond.
define shell
a group of atomic orbitals with the same principal quantum number, n, also known as a main energy level
deine sub shell
a group of orbitals of the same type within a shell
define atomic orbital
a region around the nucleus which can hold up to 2 electrons with opposite spins
