Exercises: IUPAC nomenclature: simple substances, monoatomic ions and binary compounds

The iron in a bridge ($\text{Fe}$) and the carbon dioxide we release when breathing ($\text{CO}_2$): one of the two is a simple substance and the other is a compound. The figure shows their particle models.

Which is which? Explain the difference between the two.

Many fire extinguishers are filled with $\text{CO}_2$ gas. Naming it with Greek prefixes (mono-, di-, tri-) according to the number of oxygen atoms it has, what is the name of this gas?

Using the prefixes mono-, di-, and tri-, write the formula for these two substances: carbon monoxide and carbon dioxide. What is the difference between the two molecules?

When a metal combines with a non-metal, the compound is named by placing the name of the metal first and then the name of the non-metal with the ending -ide. Apply the rule and name table salt, $\text{NaCl}$, as well as the compound $\text{CaS}$.

When a sodium atom loses an electron, it becomes $\text{Na}^+$. The figure shows the process.

1. a) Explain what an ion is.
2. b) Does $\text{Na}^+$ have a positive or a negative charge?
3. c) What is this ion called?

Name these three monatomic ions: $\text{Cl}^-$, $\text{Ca}^{2+}$ and $\text{O}^{2-}$. Hint: positive ions keep the name of the atom (for example, the $\text{Na}^+$ ion is called sodium ion) and negative ions end in -ide (for example, the $\text{S}^{2-}$ ion is called sulfide ion).

Oxygen ($\text{O}_2$), nitrogen ($\text{N}_2$), iron ($\text{Fe}$) and helium ($\text{He}$) are simple substances. Look at their formulas and state which of them form molecules, which are made up of individual atoms and whether any of them fits neither case.

Compounds of oxygen with another element are called oxides and are named "[element] oxide". Milk of magnesia from drugstores contains $\text{MgO}$: name it. Also name the compound $\text{Na}_2\text{O}$.

Fluorite, a colorful mineral, is $\text{CaF}_2$.

1. a) Name this compound (remember the ending -ide).
2. b) Now in reverse: write the formula of sodium sulfide, which has two sodium atoms for every sulfur atom.

In your bones, calcium is present as $\text{Ca}^{2+}$.

1. a) What does that $2+$ mean?
2. b) How many electrons has the calcium atom lost?
3. c) What is this ion called?

When hydrogen combines with a metal, the compound is called a hydride. Name these two compounds: $\text{NaH}$ and $\text{CaH}_2$.

Common salt is made up of $\text{Na}^+$ ions and $\text{Cl}^-$ ions arranged in a lattice. The figure shows a section of that lattice.

1. a) Explain why the same number of ions of each type is needed for the salt to be neutral.
2. b) Write the formula of the salt and reason why it cannot be $\text{Na}_2\text{Cl}$.

Classify each substance as an element, oxide, hydride, or binary salt, and write its name:

1. a) $\text{O}_2$
2. b) $\text{Na}_2\text{O}$
3. c) $\text{CaH}_2$
4. d) $\text{FeS}$
5. e) $\text{N}_2$
6. f) $\text{MgO}$