How many electrons are there in the valence shell of the oxygen atom of water?
a. 2
b. 4
c. 6
d. 8
The correct answer and explanation is:
The correct answer is c. 6.
Oxygen has an atomic number of 8, meaning it has 8 electrons in total. These electrons are arranged in two energy levels or electron shells. The first shell can hold a maximum of 2 electrons, while the second shell can hold up to 6 electrons. Therefore, in its neutral state, oxygen has 6 electrons in its outermost shell, also known as the valence shell.
In a water molecule (H₂O), each oxygen atom is bonded to two hydrogen atoms through covalent bonds. Oxygen shares one electron with each hydrogen atom to form these bonds. Despite this sharing, the oxygen atom still retains its 6 valence electrons, since it is the atom providing electrons to form the bonds. These 6 valence electrons are important in determining the chemical reactivity and bonding properties of oxygen, which is why oxygen can form two bonds with hydrogen in a water molecule.
The valence shell is critical because it is where atoms interact with each other to form chemical bonds. The number of electrons in the valence shell influences how an atom will bond with others. For oxygen, having 6 electrons in the valence shell means it is two electrons short of a full outer shell, which is why it forms bonds with hydrogen to complete its shell and become more stable.
In summary, the oxygen atom in water has 6 electrons in its valence shell, contributing to its ability to form covalent bonds with hydrogen atoms. This electron configuration is a key feature of water’s unique properties.