LEWIS DOT SYMBOLS (9.1 – 9.2)
- Write the Lewis symbols for atoms and ions.
Ionic and covalent
bonds are important types of chemical bonds. In this chapter you will
learn to use electron configurations and the periodic table to predict the
type and the number of bonds an atom of a particular element can form. Electron
configurations can be used to write the Lewis dot symbols of the representative
elements. A Lewis dot symbol
of an element consists of the chemical symbol with one or more dots placed
around it. Each dot represents a valence electron. The orbital diagram and
the Lewis symbol for the fluorine atom are shown in Figure 9.1. Fluorine has
7 electrons in its outermost principal energy level (n = 2), and therefore
has 7 dots in its Lewis symbol.
Click on the orbital diagram below to reveal the Lewis symbol.
Figure 9.1 Orbital diagram and Lewis symbol for the fluorine atom.
The Lewis dot symbols and the electron configurations of the outermost electrons
of elements in the third period are as follows:
Click on each electron configuration above to get the Lewis symbol.
For representative elements, the number of valence electrons is the same as
the group number.
EXAMPLE Lewis Dot Symbols
Write Lewis symbols for the following elements:
The representative metals form ions by losing all of their valence electrons.
Lewis symbols can be used to represent the formation of positive magnesium and
aluminum ions as follows:
The nonmetal elements form negative ions by acquiring electrons until they
are isoelectronic with a noble gas atom. Ions of nonmetal have 8 electrons
in their valence shell.
Sulfide and chloride ions, for example, have net charges of –2 and –1 because
the atoms needed 2e– and 1e–, respectively, to become isoelectronic with the noble gas argon.
EXAMPLE Lewis Dot Symbols for Ions
Write Lewis symbols for the following ions:
Complete the following questions to check your understanding of the material.
Select the check button to see if you answered correctly.
- Write Lewis dot symbols for atoms of the following elements:
- Write Lewis dot symbols for the following ions: