Chapter 5 Flashcards
What is an electron shell?
- A group of atomic orbitals with the same principal quantum number (n)
- It is also called an energy level
What is an orbital?
- A region around the nucleus that can hold up to 2 electrons with opposite spins
List 4 types of orbitals.
- s
- p
- d
- f
Describe s-orbitals.
- They are the shape of a sphere
- Every shell has 1 s-orbital
Describe p-orbitals.
- They are the shape of a dumb-bell
- Each shell from n=2 and onwards contains 3 p-orbitals
How many d-orbitals are there in each shell?
- From n=3 and onwards, there are 5 d-orbitals in each shell
How many f-orbitals are in each shell?
- Each shell from n=4 and onwards contains 7 f-orbitals
What is a sub-shell?
- A group of orbitals of the same type within a shell
How do sub-shells in the same shell compare in terms of energy?
- Each new sub-shell added has more energy than the previous one
How do the relative energy levels of the sub-shells of different shells compare?
- The sub-shells making up the first 4 shells generally stay in order from the s-orbital in n=1 having the least energy, and so on
- However, the 3d sub-shell is at a higher energy level than the 4s sub-shell
How does the amount of energy each sub-shell has affect the order sub-shells are filled in?
- Sub-shells are filled in in order of ascending energy (so 1s first, and so on)
- 4s is at a lower energy level than 3d, so it it is filled first
What do electrons-in-box models show?
- Electrons are represented by arrows that the either face up or down, which indicate its spin
- The 2 electrons in the same box must have opposite spins
Why do 2 electrons in the same orbital have opposite spins?
- This helps to counteract their repulsion
How do orbitals fill, and why?
- All orbitals within a sub-shell have the same energy
- 1 electron therefore occupies each orbital before they start to pair up (also prevents repulsion between paired electrons)
What order are sub-shells written in for electronic configuration?
- In order of shell order rather than filling order (so 3d is written before 4s)
How does the shorthand notation for electronic figurations work?
- You put the name of the previous noble gas in square brackets
- You then write the rest of the electronic configuration (if it has the same configuration as a noble gas, use the noble gas before this)
Which sub-shells are affected when atoms lose or gain electrons?
- The one with the most energy
- The 3d energy level falls below the 4s energy level when it is (even partially) filled
- The 4s energy level therefore loses electrons (as well as filling) before the 3d energy level
How is the periodic table divided into blocks?
- The blocks correspond to the elements’ highest energy sub-shell
What are the different blocks in the periodic table?
- s-block is groups 1 and 2
- p-block is groups 3 to 0
- d-block is the centre block of 10 groups
What is ionic bonding? Required.
- The electrostatic attraction between positive and negative ions
What is an ionic lattice? Required.
- A repeating pattern of oppositely charged ions
Why do ionic bonds result in the creation of a giant ionic lattice?
- Each ion attracts oppositely charged ions in all directions
Describe the melting and boiling points of ionic compounds, and explain why they are like this.
- They have high melting and boiling points
- This is because large amounts of energy are needed to overcome the strong electrostatic attraction between the ions
How do melting and boiling points differ across ionic compounds, and why?
- The melting and boiling points of lattices made of ions with greater ionic charges are higher
- This is because the ions are more strongly attracted together
What type of solvents do ionic compounds dissolve in, and how?
- Polar solvents
- Water molecules are polar and surround each ion and break down the lattice
Why does the solubility of ionic compounds differ?
- If the compound is made of ions with large charges, the ionic attraction may be too strong for the water molecules to break
Do ionic compounds conduct electricity? Explain why.
- When in the liquid state or dissolved in water
- This is because in the solid state ions are in a fixed position in the giant ionic lattice, so solid ionic compounds are non-conductors of electricity
- When they are either liquid or aqueous, the solid ionic lattice breaks down and the ions are mobile, so in the liquid or aqueous state, an ionic compound is a conductor of electricity
What is a covalent bond? Required.
- The strong electrostatic attraction between a shared pair of electrons and the nuclei of the bonded atoms
What is a dative covalent bond, and what can it also be known as? How is it shown in displayed formulae?
- A covalent bond where the shared pair of electrons is supplied by one of the bonding atoms only (these electrons were originally a lone pair)
- Coordinate bond
- An arrow goes from the atom giving the electrons to the one it’s sharing them with
What is average bond enthalpy?
- A measurement of the strength of a covalent bond (the higher the value, the stronger the covalent bond)
