Question

26 sep use models other than the names of the ions, how does the name of cas differ from the name of cds?

Explanation:

Calcium sulfide (CaS) is an ionic compound with a common - name - style naming. Cadmium sulfide (CdS) is also an ionic compound. However, Cd is a transition metal. For ionic compounds with transition metals, the charge of the metal ion (in Roman numerals) is included in the name if the metal has variable oxidation states. Cadmium in CdS has a + 2 oxidation state. But calcium (Ca) is an alkaline earth metal (Group 2A) and has a fixed + 2 oxidation state. So, the name of CdS includes a Roman numeral (if following the Stock system, it would be cadmium(II) sulfide), while the name of CaS does not (it is just calcium sulfide).

Answer:

The name of CdS includes a Roman numeral (indicating the oxidation state of Cd, e.g., cadmium(II) sulfide if using the Stock system), while the name of CaS does not (it is simply calcium sulfide) because Ca is an alkaline - earth metal with a fixed oxidation state and Cd is a transition metal with a variable oxidation state.