physical properties Flashcards
what is the size of the atom determined by ?
- number of occupied energy levels
- nuclear charge (for periods trend)
what is the pattern for atomic radius for group 2 metals ?
atomic radius increases down the group
why does the atomic radius increase down the group ?
the number of occupied energy levels increases by 1 each time so atomic radius increases down the group
what does ionisation energy depend on ?
- the strength of attraction between the nucleus and the outermost electron
ionisation energy is larger with :
- larger nuclear charge (affects pattern across a period )
- smaller atomic radius
what happens to the ionisation energy down group 2 ?
ionisation energy decreases down group 2
- atomic radius increases
- so attraction between nucleus and outer electron decreases down the group
- more shielding down the group
what is meant by the melting point ?
its the temperature at which forces between particles in a solid weaken and particles separate
what kind of bonding does group 2 have ?
metallic bonding in a 3D lattice
what are the features of metallic bonding ?
regular layers of positive metal ions
- with a sea of delocalised electrons that are free to move through the structure
what kind of ions are all the group 2 metals ? and what does this mean ?
2+ ions
- there are 2 delocalised electrons per ion
what happens to the ionic radius down the group ?
it increases
- so the charge will spread over a larger area for ions lower down group 2
what happens to the charge density down the group ? and what does this mean ?
charge density decreases down the group
- there is a weaker attraction between ions and delocalised electrons so less energy to overcome
what does charge density mean ?
charge per unit volume
