Question

Name the following compounds: (a) \(\mathrm{SnO}_{2}\) (b) \(\mathrm{Ca}(\mathrm{CN})_{2}\) (c) \(\mathrm{Na}_{2} \mathrm{CO}_{3}\) (d) \(\mathrm{Cu}_{2} \mathrm{SO}_{4}\) (e) \(\mathrm{Ba}(\mathrm{OH})_{2}\) (f) \(\mathrm{Fe}\left(\mathrm{NO}_{3}\right)_{2}\)

Short answer

(a) Tin (IV) Oxide, (b) Calcium Cyanide, (c) Sodium Carbonate, (d) Copper (I) Sulfate, (e) Barium Hydroxide, (f) Iron (II) Nitrate.

Step-by-step solution

Identify the Compound Type for SnO2

The compound \( \mathrm{SnO}_{2} \) consists of tin (Sn) and oxygen (O). Tin can have multiple oxidation states. Since oxygen is mostly in the form of oxide \((\mathrm{O}^{2-})\), we determine the oxidation state of tin \((\mathrm{Sn})\) in \( \mathrm{SnO}_{2} \) is \(+4\). Thus, \( \mathrm{SnO}_{2} \) is named as Tin (IV) Oxide.

Name Ca(CN)2

The compound \( \mathrm{Ca}( ext{CN})_{2} \) consists of calcium (Ca) and the cyanide ion (CN). Calcium has a fixed oxidation state of \(+2\). Cyanide is a polyatomic ion with the formula \( \mathrm{CN}^- \). Therefore, this compound is named Calcium Cyanide.

Name Na2CO3

\( \mathrm{Na}_{2} \mathrm{CO}_{3} \) consists of sodium (Na) and carbonate (CO3), where sodium is a metal with a fixed charge \(+1\). Carbonate is a common polyatomic ion \((\mathrm{CO}_{3}^{2-})\). Therefore, the name for this compound is Sodium Carbonate.

Name Cu2SO4

The compound \( \mathrm{Cu}_{2} \mathrm{SO}_{4} \) includes copper (Cu) and sulfate (SO4). Copper can have multiple oxidation states, and the sulfate ion \((\mathrm{SO}_{4}^{2-})\) is a common polyatomic ion. With 2 copper ions equating to \(+2\) for sulfate, each copper is \(+1\). Therefore, the compound is called Copper (I) Sulfate.

Name Ba(OH)2

\( \mathrm{Ba}( ext{OH})_{2} \) is made of barium (Ba) and hydroxide (OH). Barium has a fixed oxidation state of \(+2\), and hydroxide is \((\mathrm{OH}^-)\). Thus, the compound is named Barium Hydroxide.

Name Fe(NO3)2

The compound \( \mathrm{Fe}( ext{NO}_{3})_{2} \) consists of iron (Fe) and nitrate (NO3). Nitrate is a polyatomic ion \((\mathrm{NO}_{3}^{-})\). Iron can have multiple oxidation states, but to balance the complex, it is \(+2\) here. Therefore, the compound is named Iron (II) Nitrate.

Key concepts

Oxidation States

Understanding oxidation states is crucial when naming chemical compounds, particularly those containing transition metals. Oxidation state, also known as oxidation number, indicates the degree of oxidation of an atom in a compound. It's essentially a bookkeeping system for electrons, showing how many electrons an atom has gained or lost.

In general:

• Transition metals often have multiple oxidation states, which can complicate naming. For instance, copper can exist in either the +1 or +2 oxidation state.
• Oxygen typically has an oxidation state of -2 in compounds, which helps determine the state of the other atom in the compound.
• Some metals, like alkali metals, have fixed oxidation states because they readily lose electrons to form positive ions. For example, sodium always has a +1 oxidation state.

Knowing the oxidation state aids in writing the compound's name, especially when using Roman numerals to indicate the oxidation state of transition metals, such as in Copper (I) Sulfate (Cu₂SO₄).

Polyatomic Ions

Polyatomic ions are ions composed of two or more atoms covalently bonded, or a metal complex that acts as a single unit with a positive or negative charge. These ions are prevalent in naming ionic compounds.

Some common polyatomic ions include:

• Sulfate \(\mathrm{(SO}_{4}^{2-})\)
• Nitrate \(\mathrm{(NO}_{3}^{-})\)
• Carbonate \(\mathrm{(CO}_{3}^{2-})\)
• Cyanide \(\mathrm{(CN}^{-})\)
• Hydroxide \(\mathrm{(OH}^{-})\)

Each polyatomic ion has a specific charge, which helps balance the charges in the ionic compounds they form. For example, in iron (II) nitrate (Fe(NO₃)₂), the two nitrate ions balance the +2 charge of the iron. Understanding these ions and how they interact is essential for accurately naming and understanding chemical compounds.

Ionic Compounds

Ionic compounds are formed from the electrostatic attraction between ions. These compounds typically consist of metals and nonmetals, where metals lose electrons to form positive cations and nonmetals gain electrons to form negative anions.

Key features of ionic compounds include:

• High melting and boiling points due to strong ionic bonds.
• The formation of crystal lattice structures, contributing to their solid state.
• Electrical conductivity when dissolved in water or molten, as ions are free to move.

When naming ionic compounds:

• The metal is named first, using either its element name or with Roman numerals if multiple oxidation states are possible (e.g., Tin (IV) Oxide).
• The nonmetal or polyatomic ion follows, often with an "-ide" suffix for simple anions (e.g., Calcium Cyanide).

Understanding these properties and naming conventions can help identify and categorize a wide range of chemical compounds.

Transition Metals

Transition metals are elements found in the central block of the periodic table and are characterized by their ability to form compounds with a variety of oxidation states. This unique feature arises from their partially filled d-orbitals.

Notable properties of transition metals include:

• High melting and boiling points.
• The ability to form colored compounds due to d-d electron transitions.
• Variable oxidation states, leading to diverse chemical reactivity.
• The formation of complex ions with other elements and polyatomic ions.

When naming compounds with transition metals, it’s essential to specify the oxidation state in the compound name for clarity. This is typically done using Roman numerals, as seen with Iron (II) Nitrate (Fe(NO₃)₂) and Tin (IV) Oxide (SnO₂). Understanding transition metals and their properties is vital for mastering chemical nomenclature.