Electronic Structure Of Atoms Flashcards
What is an energy level
Shell which electrons of equal energy occupy
What is electronic configuration
How the electrons are arranged
E.g. Na 2,8,8,1
Ca 2,8,8,2
What is an energy sub level
Levels within an energy level (s,p,d,f)
Sublevels are further divided into orbitals of equal energy
What is an orbital
Region in space around the nucleus of an atom with a high probability of finding an electron
Describe the aufbau principal
Electrons will occupy the lowest energy level available
Within a sublevel orbitals are arranged from lowest to highest energy spdf
4s has lower energy than 3D!!
What is hunds rule
When two or more orbitals of equal energy are available electrons will occupy singly first and then double up
What is paulis exclusion principle
No more than two electrons can occupy an orbital and to do so they must have opposite spin
What is the atomic radius
Half the distance between the centre of singly bonded covalent atoms
What determines the size of the atomic radius of a particular atom
Nuclear charge
Number of shells of electrons screening the nuclear charge from the outer valance electrons
What happens to atomic radius going across a period
It decreases
Nuclear charge increases
This increased nuclear charge is not screened by an extra shell of electrons as all the atoms in the same period contain the same number of shells
What happens to atomic radius going down a group
It increases
Nuclear charge increases but is screened by an extra shell of electrons
An extra shell of electrons is added on
Definite first ionisation energy
Energy required to remove the most loosely bound electron from a neutral gaseous atom in the ground state
What are the 3 factors that influence the size of ionisation values
Size of nuclear charge
Atomic radius of an atom I.e. how near the electron is to the nuclear charge
Configuration of an atom - atoms with full shells or half filled sublevels have stable configurations and will require a high ionisation value
What happens across a period
Increases
Nuclear charge increases and it is not screened by an extra shell of electrons (all atoms in same period contain same no of shell)
Atomic radius decreases
What happens down a group
Decreases
Nuclear charge increases but this time it is screened by an extra shell of electrons
Atomic radius increases I.e. the electron being removed will be further away from the nucleus
