Na, Mg and Al are the elements of the 3rd period of the Modern Periodic Table having group;

CBSE Class 10 CBSE Class 10 Science
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1

Na, Mg and Al are the elements of the 3rd period of the Modern Periodic Table having group; number 1, 2 and 13 respectively which one of these elements has the

  1. highest valency,
  2. largest atomic radius, and
  3. maximum chemical reactivity ? Justify your answer stating the reason for each.
2

  1. Highest valency: 3 (Aluminium)

  2. Na (Sodium) has the largest atomic radius.
    Reason: This is due to an increases in nuclear charge which tends to pull the electrons closer to the nucleus and reduces the size of the atom.

  3. Na (Sodium) has maximum chemical reactivity. Na has greater size due to which tendency to loose electron is maximum.