Dec 20, 2015
The Periodic Table
The Periodic Table
• John Newlands – 1864 – law of octaves
The Periodic Table
• John Newlands – 1864 – law of octaves
• Dmitri Mendeleeve – first periodic table predicted missing Atoms
The Periodic Table
The Periodic TableArranged according to electronic configuration and
by increasing atomic number.
The Periodic Table
Representations in chemical equations
Metals – represented in their empirical formula Fe, Cu…..
Non Metals – no set rule – based on most common form C, P4
If diatomic
(H2, N2, O2, F2, Cl2, Br2, I2)
Sulfer - is S8 but usually used as SMetaloids – like metals use empirical
formula B, Si, Ge
Removal of Electrons
• Mn2+ has config of [Ar] 3d5
NOT [Ar] 4s23d3
• Electron filling does not predict the order of electron removal in transition metals
Atomic Radius
Size of atom – the volume that encompasses 90 % of the electron density.
Atomic Radius – one half the distance between the two nuclei in two adjacent atoms.
Determined by x-ray diffraction.