Which element has the fewest valence electrons available for bonding?
The Correct Answer and Explanation is:
Correct Answer: Lithium
Among all elements, lithium has the fewest valence electrons available for bonding. Lithium belongs to Group 1 of the periodic table, also known as the alkali metals. It has only one valence electron, which is located in the second energy level.
Valence electrons are the electrons found in the outermost energy level of an atom. These electrons are important because they are the ones involved in chemical bonding. The number of valence electrons determines how an element interacts with other atoms. Elements with fewer valence electrons tend to be more reactive, especially metals, since they can easily lose electrons to achieve a stable electron configuration.
Lithium has an atomic number of 3, meaning it has three total electrons. The first two electrons fill the first energy level, while the third electron enters the second energy level. This lone electron in the outer shell is the only one available for bonding. As a result, lithium typically forms ionic bonds by losing that one valence electron to achieve the stable configuration of helium, the nearest noble gas.
Comparing lithium to other common elements:
- Beryllium (atomic number 4) has two valence electrons.
- Boron (atomic number 5) has three valence electrons.
- Carbon (atomic number 6) has four valence electrons.
This pattern follows the periodic table. As you move from left to right across a period, the number of valence electrons increases. Lithium, being the first element in Period 2, has the smallest number of valence electrons in that period.
Therefore, lithium has the fewest valence electrons available for bonding, making it highly reactive and easily able to form chemical compounds, especially with nonmetals like halogens.
