Question

Metal ‘A’ has electronic configuration 2, 8, 1 and metal ‘B’ has electronic configuration 2, 8, 8, 2. Out of these, which metal is more reactive? Write the reaction of this metal with dilute HCl acid.

Answer 1

• Metal A is sodium (Na): 2, 8, 1.
• Metal B is calcium (Ca): 2, 8, 8, 2.
• Metal A (sodium) is more reactive than metal B (calcium).
• Chemical Reaction:
  (i) In a violent reaction, sodium metal and weak hydrochloric acid produce sodium chloride and hydrogen.
  \[\ce{2Na(s) + 2HCl(aq) -> 2NaCl(aq) + H2(g)}\]
  (ii) Calcium chloride and hydrogen are formed with less vigour.
  \[\ce{Ca + 2HCl -> CaCl2 + H2}\]