Classify each of the following as ionic or molecular, and name each:
a. Li₂HPO₄

Verified step by step guidance

1. Step 1: Identify the types of elements in the compound. Lithium (Li) is a metal, and the rest of the compound (HPO₄) contains nonmetals (hydrogen, phosphorus, and oxygen). Compounds containing metals and nonmetals are typically ionic.
2. Step 2: Confirm the ionic nature of the compound. Li₂HPO₄ is composed of lithium ions (Li⁺) and the hydrogen phosphate ion (HPO₄²⁻), which confirms it is an ionic compound.
3. Step 3: Name the cation (positive ion) first. Lithium (Li⁺) is a monatomic ion, so its name remains 'lithium.'
4. Step 4: Name the anion (negative ion) second. HPO₄²⁻ is a polyatomic ion called 'hydrogen phosphate.'
5. Step 5: Combine the names of the cation and anion. The name of the compound is 'lithium hydrogen phosphate.'

Key Concepts

Ionic Compounds

Ionic compounds are formed when atoms transfer electrons, resulting in the formation of charged ions. These compounds typically consist of a metal and a non-metal, where the metal donates electrons and the non-metal accepts them. The electrostatic attraction between the oppositely charged ions holds the compound together. An example is lithium phosphate (Li₂HPO₄), which contains lithium ions and phosphate ions.

Molecular Compounds

Molecular compounds are formed when two or more non-metal atoms share electrons through covalent bonds. These compounds usually consist of discrete molecules rather than a lattice structure, and they can exist in various states (solid, liquid, gas) at room temperature. An example is water (H₂O), where hydrogen and oxygen atoms share electrons to form a stable molecule.

Nomenclature of Compounds

Nomenclature refers to the systematic naming of chemical compounds based on their composition and structure. For ionic compounds, the name typically includes the cation (positive ion) followed by the anion (negative ion), while molecular compounds use prefixes to indicate the number of atoms present. Understanding nomenclature is essential for accurately classifying and naming compounds like Li₂HPO₄, which is named lithium hydrogen phosphate.