Atoms and Molecules

All matter around us, like your book, laptop, and even living organisms, are made up of tiny building blocks called atoms.

The center of an atom is its nucleus, which contains protons with a positive charge and neutrons with no charge.

Surrounding the nucleus are electrons with a negative charge that exist around the nucleus.

Atoms are electrically neutral when they have equal protons and electrons. But when they gain or lose electrons, they become ions carrying either a negative or positive charge.

Every atom belongs to a specific chemical element, defined by the number of protons in its nucleus. For instance, hydrogen atoms each have one proton, while oxygen atoms have eight.

Atoms can also combine to form molecules. For example, a water molecule is comprised of two hydrogen atoms bonded to one oxygen atom. Because water has a fixed ratio of hydrogen to oxygen, it’s called a compound.

Compounds are formed when two or more elements combine in specific proportions, creating unique substances like salt, sugar, medicines, or household cleaning agents.