PERIODICITY Flashcards
Describe the trend in atomic radius across a period
Decreases across the period
Increased number of protons
More positive charge attraction for electrons in the same shell
With similar shielding
Describe the trend in 1st ionisation energy across the period
Generally increases across the period
Due to an increasing number of protons
With a small drop between Group 2 and 3
With a small drop between Group 5 and 6
Describe the small drop in ionisation energy between group 2 and 3
Group 2 elements have electrons in the s subshell
While group 3 elements are starting to fill the p subshell
Group 3’s electron is easier lost because p electrons are higher in energy than s electrons
Describe the small drop in ionisation energy between group 5 and 6
Group 6’s electron is paired up with another electron in the same p orbital
When the second electron is added there is a slight repulsion between the two negative electrons
Making the second electron easier to remove
Describe the trend in melting and boiling points across the period
Increases between groups 1 and 3, with a slight decrease in BP between G3 and G4 and a further increase in MP
Decreases between G4 and G5 but slightly increases again between G5 and G6
Decreases after G6
Describe the melting and boiling points of group 1 to 3
Metallic Bonding
Stronger with more electrons in the outer shell
More electrons released to the sea
Higher energy needed to break bonds
Describe the melting and boiling point of group 4
Macromolecular/Giant Covalent Lattice
Strong covalent bonds between atoms
High energy needed to break bonds
Describe the melting and boiling point of group 5 to 7
Simple Molecular
Weak Van Der Waals between molecules
Little energy needed to break them
Group 6 slightly higher due to more electrons (more van der waals)
Describe the melting and boiling point of group 8
Monoatomic
Weak van der waals between atoms
