1. Which element forms bonds with a sea of mobile electrons?
a) Ca
b) C
c) Ar
d) He
Usually a metal. The only metal I see in the answers is Ca.
The correct answer is b) C (carbon).
To determine the correct answer, we need to understand the concept of metallic bonding. Metallic bonding occurs in elements that have a few valence electrons and a relatively low ionization energy, such as transition metals and some non-metals like carbon.
In metallic bonding, the outermost electrons of the atoms are delocalized or free to move throughout the structure, creating what is known as a "sea of mobile electrons." This electron sea enables atoms to form strong bonds with one another.
Among the given elements, only carbon (C) meets the criteria for metallic bonding. Calcium (Ca) is an alkaline earth metal and does not have a few valence electrons. Argon (Ar) and helium (He) are noble gases, which have completely filled valence electron shells and do not form metallic bonds.
Therefore, the correct answer is b) C (carbon).