Question

What is the name of PbO?

Answer 1

Hint: PbO is an ionic compound made by heating lead metal in the air. The oxygen has an ionic charge of $-2$ and since there is only one lead atom, it must be in a $+2$ oxidation state to balance the negative charge of oxygen. Now, we know the oxidation state and ions present in PbO, so we can write its name according to IUPAC nomenclature.

Complete answer:
In naming the inorganic chemical compounds, a systematic method is recommended by the International Union of Pure and Applied Chemistry (IUPAC) and that is known as IUPAC nomenclature.
According to this nomenclature method, ionic compounds are named by writing the cation name first followed by the name of its anionic counterpart. The positive ion retains its element name whereas for non-metal anion is written by adding -ide as the suffix. And to denote the number of elements present, the prefix mono-, di-, tri-, etc. is used.
Some metal elements can have more than one charge, the naming of such compounds is done by writing the charge using roman numerals in parenthesis immediately following the element’s name.
Let us consider the case of PbO. It is an ionic inorganic compound made up of lead metal and a single oxygen atom. To write its name, we need to find out the charge present on the elements.
The oxygen has the charge of $-2$ and since the overall compound should be neutral so, Pb has a $+2$ charge. The name of this compound becomes Lead (II) monoxide.

Hence, the name of PbO is Lead (II) monoxide.

Additional information:
Lead monoxide is an amphoteric oxide and it has some other common names – litharge, massicot, plumbous oxide, and galena.

Note:
There are some exceptions while writing roman numerals in ionic compounds. For example, aluminium, zinc, and silver. Roman numerals are not used to write after the names of these elements in a compound as they exist only in a single ion.