Predicting the type of bond

In many cases, you will need to predict the type of bond present. We will be giving you several tips along the way to help you decide. Electronegativity is a tool that you can use in predicting bond type. This tool will also help you to make other predictions. 

Compounds have a certain fixed proportion of elements. The periodic table often can be used to predict the type of bonding that might exist between elements. The following general guidelines apply ... 

There are several methods you can use to predict the type of bond in an unknown substance. For example, you can consider the substance s physical properties. In contrast to ionic solids, covalent (molecular) compounds typically have the following properties ... 

The type of bonding in a substance depends upon the kinds of atoms it contains and the forces of attraction between those atoms. If you know the physical properties of a substance, you can often predict the type of bonding in the substance. Table 4.5 summarizes the types of forces of attraction and the physical properties of solids with different types of bonding discussed in this section. In Investigation 4-B, you will design an experiment in which you predict the type of bonding in various substances, then test your prediction. 

Lewis structures help us to track the valence electrons and predict the types of bond. The number of valence electrons present in each of the elements is to be considered first. The number of valence electrons determines the number of electrons needed to complete the octet of eight electrons. Simple ions are atoms that have gained or lost electrons to satisfy the octet rule. However, not all compounds follow the octet rule. 

How can the electronegativity difference help you predict the type of bond By the end of this section, you will understand the aswer to this question. Consider three different substances potassium fluoride, KF, oxygen, O2, and hydrochloric acid, HC1. Potassium fluoride is an ionic compound made up of a metal and a non-metal that have very different electronegativities. Potassium s electronegativity is 0.82. Fluorine s electronegativity is 3.98. Therefore, AEN for the bond between potassium and fluorine is 3.16. 

In this section, you learned that most elements do not exist in their pure form in nature. Rather, they exist as different compounds. You reviewed the characteristic properties of ionic and covalent compounds. You considered the periodic nature of electronegativity, and you learned how to use the electronegativity difference to predict the type of bond. You learned, for example, that ionic bonds form between two atoms with very different electronegativities. 

Thinking Criticaiiy Predict the type of bond that will form between the following atoms. 

In this chapter we will learn to use electron configurations and the periodic table to predict the type of bond atoms will form, as well as the number of bonds an atom of a particular element can form and the stability of the product. 

List all the possible bonds that can occur between the elements P, Cs, 0, and H. Predict the type of bond (ionic, covalent, or polar covalent) one would expect to form for each bond. 

The uses of electronegativity values are that they help to predict the type of bonding to be ejqjected in a molecule, as well as the polarity of co ent molecules. The greater the difference in electronegativity values between the combining elements, the more likelihood of an ionic bond the closer the values, the more likelihood of a covalent bond. 

Predict the type of bond formed between each of the following pairs of elements ... 

Use Table 4.4 and predict the type of bond you would expect to find in compounds formed from the following elements ... 

Deduce the difference in electronegativity in the following bonds and predict the type of bonding chlorine-chlorine, hydrogen-fluorine, carbon-chlorine, beryllium-chlorine and carbon-hydrogen. 

Using electronegativity values from Table 4.3, predict the type of bonding in fluorine molecules (Fj), hydrogen iodide (HI) and lithium fluoride (LiF). ... 

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