Elements X, Y and Z have atomic numbers 6, 9 and 12 respectively. State the type of bond between Y and Z and give its molecular formula.

 Question:

Elements X, Y and Z have atomic numbers 6, 9 and 12 respectively. State the type of bond between Y and Z and give its molecular formula.

Solution:

Electrovalent bond will be formed between Y and Z and its molecular formula will be ZY₂.

Explanation:

Write the electronic configuration of the three elements.

 X with atomic number 6- 2, 4

Y with atomic number 9- 2, 7

Z with atomic number 12- 2, 8, 2

Y will gain one electron, so its valency is 1 and Z will lose 2 electrons so its valency is 2. The atom which loses electrons is written first as in NaCl, MgCl_{2  , so here Z will be written first.}

_{Applying criss-cross method,} 

Z     Y

2      1

1 will go to Z and 2 will go to Y

So, the formula will be ZY₂.