Question

A compound is formed between atoms A and B. The electronic configuration of A is 2, 8, 1 and B is 2, 6.

1. Write the equation of the formation of ions of A and B.
2. Why do A and B form ions?
3. Which of the following can form a compound?
   1. A and A
   2. A and B
   3. B and B
      Also state the type of bonding present in the compound.
4. If A and B combines, which of them will get oxidised?
5. Draw an electron dot diagram of the ionic compound formed in part (c).
6. Write the formula of the compound formed in part (c) which has a
   1. high melting and boiling point
   2. gaseous compound
   3. good conductor of electricity in molten state.

Answer 1

1. Atom A loses one electron
   \[\ce{A -> A+ + e-}\]
   Atom B gains two electrons
   \[\ce{B + 2e- -> B^{2-}}\]
2. A and B form ions to achieve a stable noble gas configuration:
   A loses 1 electron and becomes A⁺ with a configuration of 2, 8 (like neon).
   B gains 2 electrons and becomes B²⁻ with a configuration of 2, 8 (also like neon).
3. A and B can form a compound, electrovalent bonding will be present in it.
4. Oxidation is the loss of electrons. A (sodium) loses 1 electron to form Na⁺. Hence A gets oxidised.
5. 
   
6. 1. A₂B
   2. A and B will not form a gaseous compound.
   3. A₂B