Periodicity

Mendeleev: He arranged elements in order of atomic mass and lined up in groups with similar properties. Left gapsif group properties did not fit for elements not discovered and if some atomic mass measurements were wrong. Potassium and argon are not arranged in...

Semi- Metals: Elements near the diagonal divide are semi- metals or metalloids with in- between properties. • Metallic Bonding: The electrostatic attraction between positive metal ions and delocalised electrons. • Giant Metallic Lattice: Each atom has donated its...