Group and Period of

Periodic Table

Group

• Groups are the vertical columns of the periodic table

• Group number of an element=Number of valence electron the element has

• Elements in the same group have similar chemical properties as they have the same number of outer electrons

• The metals in the middle section of the periodic table has no group and is known as transition metals

Period

• Periods are the horizontal rows of the periodic table

• Period Number of an Element=Number of Electron Shells of an Element

• Across the period from left to right,– The amount of outer electron increase– The amount of electron shells remains the

same

– The chemical and physical properties change from the properties of a metal to the properties of a non-metal e.g. the electricity conductivity of the elements change from good to poor across the period from left to right; the bonding of the element with another element change from ionic bond to covalent bond

• An atom electrically neutral will have number of protons=number of electrons

• The amount of electron shells in an atom is determined by the number of electrons in an atom

• The elements are arranged according to their amount of outer electron shells in each period

• Since the elements are arranged according to their outer electron shells in each period, the period number = number of electron shells