Question

cdcl₂ ca(oh)₂ cobalt k₂cro₄ oxygen cocl₂ h₂ ni helium chlorine so₂ c₂h₆ single atoms diatomic molecules molecules formula units

Explanation:

• Single atoms: These are elements that exist as individual atoms. Cobalt (Co), Nickel (Ni), and Helium (He) are examples. Cobalt and Nickel are metals that typically exist as single atoms in their elemental form, and Helium is a noble gas that exists as single atoms.
• Diatomic molecules: These are molecules composed of two atoms. Oxygen (\(O_2\)) and Chlorine (\(Cl_2\)) are diatomic. In nature, oxygen commonly exists as \(O_2\) molecules and chlorine as \(Cl_2\) molecules.
• Molecules: These are groups of atoms bonded together. \(H_2\) (diatomic, also a simple molecule), \(SO_2\) (sulfur dioxide with one sulfur and two oxygen atoms), and \(C_2H_6\) (ethane with two carbon and six hydrogen atoms) are molecules.
• Formula units: These are the simplest ratio of ions in an ionic compound. \(CdCl_2\) (cadmium chloride), \(Ca(OH)_2\) (calcium hydroxide), and \(K_2CrO_4\) (potassium chromate) are ionic compounds represented by formula units.

Answer:

• Single atoms: Cobalt, Ni, Helium
• Diatomic molecules: Oxygen, Chlorine
• Molecules: \(H_2\), \(SO_2\), \(C_2H_6\)
• Formula units: \(CdCl_2\), \(Ca(OH)_2\), \(K_2CrO_4\)