Section 2 Types of Bonds

Essential Questions What are ionic bonds and covalent bonds? Which particles are produced by different types of bonding? How do nonpolar and polar covalent bonds compare?

Review Vocabulary atom: the smallest piece of matter that still retains the properties of the element

New Vocabulary ion polar bond ionic bond polar molecule covalent bond nonpolar molecule molecule nonpolar bond

Ions Atoms, too, lose or gain to meet a standard—stability. They do not lose or gain an advantage. Instead, atoms lose or gain electrons. An atom that has gained or lost an electron is called an ion. An ion is a charged particle that has either more or fewer electrons than protons. When an atom loses electrons, it becomes a positively charged ion known as a cation. When an atom gains electrons, it becomes a negatively charged ion known as an anion. The electric forces between oppositely charged particles can hold ions together. (l)Matt Meadows/McGraw-Hill Education, (r)SPL/Science Source

Molecules Some atoms of nonmetals are unlikely to lose or gain electrons. For example, group 14 elements would have to either gain or lose four electrons to achieve a stable outer energy level. The loss of this many electrons takes a great deal of energy. Each time an electron is removed, the nucleus holds the remaining electrons even more tightly. Therefore, these atoms become more chemically stable by sharing electrons, rather than by becoming ions. The attraction that forms between atoms when they share electrons is known as a covalent bond. The neutral particle that forms as a result of electron sharing is called a molecule.

Assessment 1. What is the name of CuO? copper oxide copper(I) oxide B copper(II) oxide C CORRECT copper(III) oxide D

Assessment 2. Which of the following formulas represents a nonpolar molecule? N2 A CORRECT H2O B NaCl C HCl D

Assessment 3. How many electrons are in the outer energy levels of the highlighted group of elements? 1 A 2 B 7 C CORRECT 17 D

Assessment 4. Which of these is an example of a covalent compound? sodium chloride A calcium fluoride B calcium chloride C sulfur dioxide D CORRECT