Periodic Table of Elements

• Johann Dobereiner - grouped the elements in a triad and increase mass
• John Newlands - was the one who created the first periodic table and discovered the law of octaves
• Who are the two scientists that made observations of elements, arranged elements with increasing atomic masses and its same group?

  Dmitri Mendeleev

  Julius Meyer
• Henry Moseley arranged the elements in increasing atomic number
• Metalloids have an intermediate properties between metals and non-metals.
• Metals have moderate to high melting points, good conductors of electricity and heat, and are malleable and ductile
• Non-metals are dull, lower melting pints, poor conductors of heat and electricity
• Electronic Configuration is the arrangement of the electrons around the nucleus
• what is the meaning of SPDF?

  Sharp

  Principal

  Diffuse

  FUndamental
• What are the max numbers of SPDF?

  S - 2

  P - 6

  D - 10

  F - 14
• Groups represent the number of valence electrons an element have
• Periods represent the energy level of electrons
• To which block in the periodic table of elements do group 1 and 2 belong?

  s-block
• the elements in the modern periodic table is arranged by increasing of atomic number and decreasing of atomic mass
• Ionization energy is the energy needed to remove an electron from an atom