can anyone explain to me this i don't understand it.
Radicals
Certain groups of different atoms will join together and act
as a single unit when forming compounds. Such a group
of atoms is called a radical. In the compound calcium
carbonate, written CaCO3, the carbonate group CO3 is
a radical. The carbonate group has a negative valence of 2,
and it combines directly with one atom of calcium, which
has a positive valence of 2. Some other examples of radicals
are sulfate (SO4
–2), nitrate (NO3
–1), hydroxide (OH–1), and
ammonium (NH4
+1).
If a subscript is needed with a radical, the symbol for the
radical is placed inside parentheses. Thus, the formula for
magnesium nitrate is written Mg(NO3)2.
The radical, as defined above, is the name of a group of elements that are grouped together, along with a negative or positive sign. I was taught this when I was in college and graduate school and I taught it to students through the 70s. However, the term has been changed and today the unit is called a polyatomic ion. Frankly, I think the new name stinks; unfortunately, it is used throughout chemistry now and I have no choice but to follow. The old term of radical is reserved for organic chemistry and it refers to "free radicals." Enough of the soap box.
The description you have sounds clear to me and it is well illustrated with numerous examples. If you will clarify what you don't understand about the term polyatomic ions, I shall be happy to help guide you to an understanding.
Of course! I'd be happy to explain it to you.
In chemistry, radicals refer to certain groups of atoms that act as a single unit when they combine with other atoms to form compounds. These radicals typically have a specific charge associated with them.
Let's take the example of the compound calcium carbonate (CaCO3). In this compound, the carbonate group (CO3) is considered a radical. The carbonate group has a negative valence of 2, which means it carries a charge of -2.
When calcium carbonate is formed, the carbonate radical (CO3) combines directly with one atom of calcium (Ca), which has a positive valence of 2. This positive and negative charge combination allows the two elements to bond together and form the compound.
There are other examples of radicals as well, such as sulfate (SO4^2-), nitrate (NO3^-), hydroxide (OH^-), and ammonium (NH4^+). These radicals also have specific charges associated with them.
When writing the formulas for compounds that contain a radical, a subscript may be required to denote the number of times the radical appears in the compound. In this case, the symbol for the radical is placed inside parentheses.
For example, consider magnesium nitrate (Mg(NO3)2). In this compound, there are two nitrate radicals (NO3) present for each atom of magnesium (Mg). The (NO3) in parentheses indicates that the entire nitrate group is repeated twice in the compound.
I hope this explanation helps clarify the concept of radicals and their role in compound formation. Let me know if you have further questions!