Atom vs Ion
The single elements are hardly stable under natural conditions. They form various combinations between them or with other elements in order to exist. Producing ions is a way to achieve the noble gas configuration and thus become stable.
Atoms are the small building blocks of all existing substances. They are so tiny that we can’t even observe with our naked eye. Normally atoms are in the Angstrom range. Atom is made up of a nucleus, which has protons and neutrons. Other than neutrons and positrons, there are other small sub atomic particles in the nucleus. There are also electrons circling around the nucleus in orbitals. Most of the space in an atom is empty. The attractive forces between the positive charged nucleus (positive charge due to protons) and the negatively charged electrons maintain the atom’s shape. Atoms of the same kind have similar protons and electrons. Same type of atoms may differ due to the number of neutrons present, and these are known as isotopes. Atoms can join with other atoms in various ways, thus form thousands of molecules. All elements have a diatomic or polyatomic arrangement to become stable except the Noble gases. According to their electron donating or withdrawing abilities, they can form covalent bonds or ionic bonds. Sometimes, there are very weak attractions between atoms.
Atom’s structure was determined by series of experiments carried out by various scientists. According to the Daltons theory,
• All matters are made out of atoms and atoms can’t be broken down further.
• All atoms of a given element are identical.
• Compounds are formed by the combination of two or more atoms.
• Atoms cannot be made or destroyed. A chemical reaction is a rearrangement of atoms.
However, there are some modifications in the Daltons theory now with the more advanced finding about the atom.
Ions are charged species with a positive or a negative charge. Positively charged ions are known as cations and negatively charged ions are known as anions. When forming a cation, an electron from the atom is giving out. When forming an anion, an electron is obtained to the atom. Therefore, the number of electrons in an ion is different from the number of protons. Ions can have -1 or +1 charges, which we call as monovalent. Likewise, there are divalent, trivalent, etc charged ions. Since cations and anions have opposite charges, they are attracted to each other with electrostatic forces, forming ionic bonds. Cations are usually formed by metal atoms and, the anions are formed by nonmetal atoms. For example, Sodium is a group 1 metal, thus forms a +1 charged cation. Chlorine is a nonmetal and has the ability to form a -1 charged anion.
What is the difference between Atom and Ion?
• Atoms haven’t obtained the noble gas configuration except the group VIII elements, but ions have obtained a noble gas configuration.
• Atoms are uncharged species, but ions have a positive or a negative charge.
• Usually in an atom the number of electrons and protons are the same, but in an ion, they are not the same. The number of electrons may be higher or lower than the number of protons.
• Ions can easily form compounds compared to atoms.
• Ions are more stable than atoms.
• The size of ions is different than that of the atoms.