Question

The atomic numbers of 4 elements $W,XY$ and $Z$ are 8, 9, 11 and 16 respectively. The covalent bond is formed between:

• A. $W$ and $Y$
• B. $Y$ and $Z$
• C. $X$ and $Y$
• D. $W$ and $Z$

Answer 1

Answer: (D)

$W$ and $Z$

A covalent bond thus holds two atoms close together because electrons in their outermost orbitals are shared by both atoms. Most of the molecules in living systems contain only six different atoms: hydrogen, carbon, nitrogen, phosphorus, oxygen and sulphur.

The double bond between sulphur and oxygen or carbon atoms can be found in compounds such as $S{O}_2$. Elemental oxygen consists of $O_2$ molecules in which each atom completes its octet of valence electrons by sharing two pairs of electrons with a single neighbouring atom.