Question

Based on the octet rule you would expect a carbon atom to make _____ covalent bonds while an oxygen atom would make ______covalent bonds. Fill in the blanks with the answer choices that correctly complete the sentence. a) 4 ; 2 b) 2 ; 4 c) 2 ; 2 d) 4 ; 3 e) 8 ; 8

Answer 1

Answer: a) 4,2

The number of covalent bonds an atom makes depends upon the valence electrons. A valence electron is located in the outermost shell (valence shell) of the atom and can be transferred to or shared with another atom.

As per the Octet rule the atoms that participate in covalent bonding share electrons in such a way that enables them to acquire a stable electronic configuration, or full valence shell.

Carbon (4 electrons in the valence shell) combines with four hydrogen atoms to form a stable covalent compound where it shares 8 electrons, while each hydrogen shares 2. Thus every atom in this stable molecule fulfills the octet rule. A carbon atom has four electrons in its outermost valence shell. So, it needs four more electrons to complete its octet. A carbon atom completes its octet only by sharing its valence electrons with other atoms. As a result, a carbon atom forms four covalent bonds by sharing valence electrons with other atoms.

Oxygen atoms can each form two covalent bonds. A oxygen atom has 6 electrons in the outermost orbit. Oxygen atom needs two more electrons to achieve the octet rule (8 valence electrons) and become most stable.