1/9/2024 0 Comments Simple diagrams of atoms![]() ![]() The resulting compounds are called ionic compounds. ![]() Because opposite charges attract (while like charges repel), these oppositely charged ions attract each other, forming ionic bonds. Those that lose electrons become positively charged, and those that gain electrons become negatively charged. Because some atoms will lose electrons and some atoms will gain electrons, there is no overall change in the number of electrons, but with the transfer of electrons the individual atoms acquire a nonzero electric charge. One way is the transfer of electrons between two atoms until both atoms have octets. There are two ways for an atom that does not have an octet of valence electrons to obtain an octet in its outer shell. This useful rule of thumb is called the octet rule, and it is a key to understanding why compounds form. Chemists have concluded that atoms are especially stable if they have eight electrons in their outermost shell. What else do the noble gas elements have in common? Except for helium, they all have eight valence electrons. These elements-helium, neon, argon, krypton, xenon, and radon-do not form compounds very easily, which suggests that they are especially stable as lone atoms. What causes atoms to make a chemical bond with other atoms, rather than remaining as individual atoms? A clue comes by considering the noble gas elements, the rightmost column of the periodic table. Chemical bonds are formed when electrons in different atoms interact with each other to make an arrangement that is more stable than when the atoms are apart. 3.1 Two Types of BondingĪtoms can join together by forming a chemical bond, which is a very strong attraction between two atoms. We will see additional examples of such differences in section 3.3 of this chapter covering “Covalent Bonding and Simple Molecular Compounds”, as we consider how atoms combine to form compounds. Nevertheless, the compound has properties completely different from either elemental sodium (a chemically reactive metal) or elemental chlorine (a poisonous, green gas). Table salt, as we have seen, consists of only two elements: sodium and chlorine. Compounds can be very complex combinations of atoms, but many important compounds are fairly simple. There are only 118 known chemical elements but tens of millions of known chemical compounds. 3 Covalent Bonding and Simple Molecular Compounds Covalent Bonds Electron Sharing Covalent Bonds Between Different Atoms Multiple Covalent Bonds 3.4 Chapter Summary Ionic Compounds Covalent Compounds 3. 2 Ions Electron Transfer Lewis Diagrams 3. This text is published under creative commons licensing, for referencing and adaptation, please click here. For the interactive PDF, adobe reader is required for full functionality. However, it's easy to determine the configuration of electrons for heavier elements by making a chart.This content can also be downloaded as a PDF file. If there are more electrons than protons, the ion has a negative charge and is called an anion.Įlements are shown from atomic number 1 (hydrogen) up to 94 (plutonium). If there are more protons than electrons, an atomic ion has a positive charge and is called a cation. The isotope is defined by the number of neutrons in an atom, which might be equal to the number of protons-or not.Īn ion of an atom is one in which the number of protons and electrons is not the same. Remember, a neutral atom contains the same number of protons and electrons. The upper right side shows the number of electrons in a neutral atom. The element atomic number and name are listed in the upper left. The final ring or shell of electrons contains the typical number of valence electrons for an atom of that element. The electron shells are shown, moving outward from the nucleus. Here are electron shell atom diagrams for the elements, ordered by increasing atomic number.įor each electron shell atom diagram, the element symbol is listed in the nucleus. ![]() For that, we have electron shell diagrams. It's easier to understand electron configuration and valence if you can actually see the electrons surrounding atoms. ![]()
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