Atoms join together to form5/5/2023 ![]() ![]() For example hydrogen is very rarely found in nature as a single hydrogen atom. In a covalent bond a pair of electrons is equally shared among two or more atoms. They both have their last shell filled with electrons.Īctivity: Draw Lewis dot diagrams to explain the formation of the magnesium chloride molecule and the potassium chloride molecule during ionic bonding. Note that in the process of bonding both atoms become octet stable. The two ions attract each other and join forming a new substance called sodium chloride. The chlorine atom gains one electron and becomes a negative ion. When sodium bonds with chlorine, the sodium atom loses one electron and becomes a positive ion. This diagram illustrates the formation of sodium chloride. Other examples of ionic bonding are Potassium Fluoride (KF), Magnesium Iodide (MgI2). Therefore they arrange themselves in a regular structure called a lattice. In these types of substances the positive ions and the negative ions alternate at regular intervals due to the attractive forces acting between them. Most crystalline substances will form ionic bonds. The electrons lost by one atom will be "grabbed" by the other atom.Īn example of ionic bonding is the one formed between sodium and chlorine when they form Sodium Chloride (NaCl - table salt). In ionic bonding one or more negative ions will join with one ore more positive ions. These atoms form positive ions or cations An atom which gains one or more electrons forms negative ions because it will have an overall negative charge now, (there are more electrons than protons in the atom now). An atom which loses one or more electrons has an overall positive charge (there are more protons than electrons in the atom now). they have equal number of protons and electrons (positive charges = negative charges). Atoms in their natural state are neutral. An ion is an atom which has gained or lost one or more electrons. This method is known as the Lewis-dot diagram (from the chemist who first thought about using this type of representation).įor ionic bonding to occur atoms bust become ions first. We can simply write the symbol of the atom and a dot for each valence electron around it. We can use the number of valence electrons to represent the atom using an alternative method to the Bohr diagram. Therefore the valence number for sodium is 1. The number of electrons used for bonding is the valence number or the number of electrons found in the outer shell.Įxample: Let's start by taking a look at the Sodium Atom's atomic diagramįrom the above we can see that the sodium atom has one electron in its last shell. ![]() They will "bond" with other atoms and in so doing they will achieve this "octet stability" state. ![]() To to this they will use one of the three methods above. This means that they will have room to place one or more electrons or to lose one or more electrons in order to achieve stability and look like the noble gases. Therefore these atoms also known as "inert" (non reactive) do not have a "need" to join with other atoms to fill their outer shells.Īpart from the noble gases, most other elements found in the periodic table will have an incomplete outer shell. This phenomenon does not allow for extra electrons to be placed in the outer shells of these atoms. ![]() Noble gases are stable elements because their last orbital (or shell) is completely filled with electrons. The octet rule of stability tells us that all atoms "aspire" to be like noble gases. Why do atoms join other atoms to form new substances called molecules? This type of bonding is called metallic bonding. This mainly takes place in metallic elements and explains the many properties of metals. Some elements are surrounded by a cloud of free electrons which are shared among all atoms of the same element. This sharing type of bonding is called molecular or covalent. They can be shared between two different atoms or they can be shared among the same element of the same atom. They can either be electrostatically moved from the atom of one element to another atom of a second element. There are three general ways in which electrons play a role in bonding. During bonding electrons are involved in "fusing or gluing" two or more atoms together. In general, bonding is a chemical change that occurs during chemical reactions. The process of two or more atoms joining together to form a molecule is called bonding. ![]()
0 Comments
Leave a Reply. |