As a chemist with a keen interest in atomic interactions, I find the topic of why atoms combine together to be quite fascinating. The behavior of atoms and their propensity to form compounds with one another is governed by the principles of quantum mechanics and the desire to achieve a stable electron configuration.

Atoms are the basic building blocks of matter and are composed of a nucleus, which contains protons and neutrons, and electrons that orbit the nucleus in discrete energy levels or shells. The outermost shell, also known as the valence shell, plays a critical role in determining how an atom interacts with other atoms. The number of electrons in this valence shell is what drives the atom's reactivity and its ability to form chemical bonds.

Atoms are always in search of stability, and one of the primary ways they achieve this is by having a full outer electron shell, which is also referred to as an "octet" in the case of elements that follow the octet rule. This is because a full outer shell provides a lower energy state and is therefore more stable. When an atom's valence shell is not full, it will interact with other atoms to fill this shell, thereby achieving a more stable configuration.

There are three primary ways in which atoms can achieve a stable electron configuration:


1. Gain of Electrons: An atom can gain electrons to fill its valence shell. This is characteristic of metals, which tend to lose electrons to achieve stability. When a metal atom donates an electron to another atom, it forms a positive ion or cation. The atom that gains the electron becomes a negative ion or anion.


2. Loss of Electrons: Conversely, some atoms, particularly nonmetals, can achieve stability by losing electrons from their valence shell. This leaves them with a full outer shell and results in the formation of a cation.


3. Sharing of Electrons: The most common way atoms achieve stability is by sharing electrons. This process is known as covalent bonding. Atoms share one or more pairs of electrons to fill their valence shells. The shared electrons are counted as part of the valence shell for both atoms involved in the bond.

The type of bond formed and the reactivity of an atom are also influenced by the electronegativity of the atoms involved. Electronegativity is a measure of an atom's ability to attract electrons in a chemical bond. When two atoms with significantly different electronegativities form a bond, the more electronegative atom will attract the shared electrons more strongly, leading to a polar covalent bond. If the electronegativity difference is very large, the bond may be ionic.

In summary, atoms combine together to form compounds primarily to achieve a stable electron configuration in their valence shell. This is done through the processes of gaining, losing, or sharing electrons. The nature of the bonds formed and the types of compounds created are determined by the specific properties of the atoms involved, including their electronegativity and the number of valence electrons.

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Most interactions among atoms take place in the outermost shell of each atom. The number of each electron in this shell determines how an atom combines with other atoms to form compounds. When atoms combine they gain, lose or share electrons in such a way that the outer shells become chemically complete.Dec 23, 2016read more >>