Modern Periodic Table

• The elements are arranged in order of increasing proton number.
• This order is also related to the electron arrangement of the elements.
• The periodic table is a classification of the element based on its chemical properties.
• There are 18 groups of elements.
  • Group 1: Element (Li, Na, K, Rb, Cs, Fr) are called alkali metals
  • Group 2: Element that known as alkaline earth metal (Be, Mg, Ca, Sr, Ba, Ra)
  • Group 17: Elements (F, Cl, Br, I, At) are known as halogen

The Electron Arrangement of Element in the Periodic Table

• All members of the same group have the same number of valence electrons.
• The number of the period is indicated by the number of shells filled with electrons.