- Newland's Octaves:
- elements in groups have similar properties
- didn't leave gaps for undiscovered elements
- metals and non metals are mixed up
- Mendeleev
- arranged by mass
- left gaps
- some elements in wrong order
- now arranged in order of atomic number
LHS metals RHS Non-metals
Groups- elements that have the same number of outer shells are part of the same group
They have similar chemical properties and physical appearance is similar
Periods- number of electrons or protons increases across period recurring patterns
Transition Elements
- metals
- hard/strong
- high melting points
- unreactive
- act as a catalyst
- form a coloured compound
- 3rd shelll being filled across period
