Classifying Particles

An atom is the smallest unit of matter that retains the properties of an element. It consists of a nucleus made of protons and neutrons, surrounded by electrons.

A molecule is a group of two or more atoms bonded together. It can consist of the same or different elements, such as $$O_2$$ (oxygen molecule) or $$H_2O$$ (water molecule).

A formula unit is the lowest whole number ratio of ions in an ionic compound. It represents the simplest form of the compound, such as $$NaCl$$ for sodium chloride.

An example of an atom is $$Xe$$ (Xenon), which is a noble gas and exists as single atoms.

An example of a molecule is $$O_2$$ (oxygen), which consists of two oxygen atoms bonded together.

An example of a formula unit is $$ZnSO_4$$ (zinc sulfate), which represents the ratio of zinc ions to sulfate ions.

A molecule is formed by covalent bonds between atoms, while a formula unit represents the simplest ratio of ions in an ionic compound.

The subscript indicates the number of atoms of each element in a molecule or formula unit. For example, in $$H_2O$$ , the '2' indicates there are two hydrogen atoms.

A compound is a substance formed when two or more elements chemically bond together, while a mixture is a combination of two or more substances that retain their individual properties.

Protons are positively charged particles found in the nucleus of an atom. They determine the atomic number and identity of the element.