What is an orbital?
A region that can hold up to two electrons with opposite spins
What is the shape of an s-orbital?
Spherical
What is the Shape of a p-orbital?
Dumbell
What is the first ionisation energy?
Is the enthalpy change when ONE MOLE of electrons is removed from ONE MOLE of gaseous atoms to form ONE MOLE of gaseous positive ions
What is the successive ionisation energy?
Successive ionisation energies are a measure of the energy required to remove each electron in turn from an atom
What is Aufbau Principle?
Electrons will fill lower energy orbitals before higher energy ones
What is the Pauli Exclusion Principle?
No to electrons can have the same four quantum numbers. The means that electrons in the same orbital have opposite spins
What is Hund’s rule?
Every orbital in a sub shell (s,p,d,f) is singly occupied before any orbital is doubly occupied. Electrons in singly occupied orbitals will have the same spin.
What is the difference between shells, sub shells and orbitals?
- Shells are the principle quantum number/ energy level (1,2,3 or 4)
- A sub shell is what each shell is split into: s,p,d,f and with each shell you gain a sub shell
- Orbitals are regions that can hold up to tow electrons with opposite spins so:
1. The s subshell has 1 orbital and so can hold 2 electrons
2. The p sub shell has 3 orbitals and so can hold 6 electrons
3. The d sub shell has 5 orbitals and so can hold 10 electrons
4. The f sub shell has 7 orbitals and so can hold 14 electrons - Only 2 electrons max. can be in a orbital!
What factors affect ionisation energy?
- Distance from the nucleus
- Nuclear Charge
- Shielding
- Charge on ion
What is an isotope?
Isotopes are atoms of the same element with different numbers of neutrons and therefore different mass numbers. The atomic number remains the same
What is the relative isotopic mass?
The mass of an isotope relative to 1/12th of the mass of an atom of carbon-12
What is the relative atomic mass?
The man mass of an element relative to 1/12th the mass of an atom of carbon-12
What is the relative molecular mass?
The sum of the relative atomic masses in simple covalent molecules and diatomic elements e.g. nitrogen (N2)
What is the relative formula mass?
The sum of the relative atomic masses in compounds with giant structures e.g. sodium chloride
Why are the second ionisation energies of calcium and strontium greater than their first ionisation energies?
Removing an electron from a more positive ion
Why do successive ionisation energies increase with ionisation number?
- Radius decreases
2. Attraction between (the remaining) electron and nucleus increases
How do the first ionisation energies of Mg (738) and Al (578) show details of electron structure?
- Mg has oute electron in 3s sub shell
- Al has outer electron in 3p sub shell
- 3p subshell has higher energy than 3s sub shell
