Ion Formation and Bonds

Essential Questions

•What holds atoms together in a chemical bond?

•How do positive and negative ions form?

•How does ion formation relate to electron configuration?

Ion Formation
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Valence Electrons and Chemical Bonds

•A chemical bond is the force that holds two atoms together.

•Chemical bonds form by the attraction between the positive nucleus of one atom and the negative electrons of another atom.

•Atom’s try to form the octet—the stable arrangement of eight valence electrons in the outer energy level—by gaining or losing valence electrons.

Ion Formation
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Positive Ion Formation

•A positively charged ion is called a cation.

•This figure illustrates how sodium loses one
valence electron to become a sodium cation.

Ion Formation
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Metal Ions

•Metals are reactive because they lose valence electrons easily. This table summarizes the ions formed by metal ions in groups 1, 2, and 13.

Ion Formation
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Transition Metal Ions

•Transition metals commonly form 2+ or 3+ ions, but can form greater than 3+ ions. Other relatively stable electron arrangements are referred to as pseudo-noble gas configurations.

Ion Formation
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Negative Ion Formation

•An anion is a negatively charged ion.

•The figure shown here illustrates chlorine gaining
an electron to become a chlorine ion.

•As shown in the table below, nonmetal ions gain
the number of electrons required to fill an octet.

•Some nonmetals can gain or lose other numbers of electrons to complete an octet.

Ion Formation
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