Which of the following is a monatomic cation?
Br
NH4+
SO42–
Fr+
Fr+ is positively charged and has one atom
cation has positive charge, mono means one so the only option would be Fr+
A monatomic cation is a positively charged ion consisting of a single atom. Among the options provided, the monatomic cation is Fr+ (Francium ion).
To determine which of the options is a monatomic cation, we need to understand what a monatomic cation is. A cation is an ion that has a positive charge, meaning it has lost electrons. Monatomic cations are formed when an atom loses one or more electrons.
Let's look at the options:
- Br: This is a bromine atom, which is not a monatomic cation because it has not lost any electrons.
- NH4+: This is the ammonium ion, which is actually a polyatomic cation composed of one nitrogen atom and four hydrogen atoms. It is not a monatomic cation.
- SO42–: This is the sulfate ion, which is a polyatomic anion composed of one sulfur atom and four oxygen atoms. It is not a monatomic cation.
- Fr+: This is the francium ion, which is a monatomic cation. Francium is in Group 1 of the periodic table and readily loses one electron to form a +1 charge.
Therefore, the answer is Fr+ - francium ion is an example of a monatomic cation.