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Next, we turn attention to group 17, the halogens, to see how properties of these elements compare. This group is located in the next to last column on the right side of the periodic table.
Next, we turn attention to group 17, the halogens, to see how properties of these elements compare. This group is located in the next to last column on the right side of the periodic table.
In nature, these elements do not exist as single atoms. Instead, two atoms associate to form a molecule. A molecule is a particle consisting of two or more atoms bonded together by sharing electrons. Thus, fluorine exists as a molecule of two fluorine atoms, and this molecule is symbolized as F2. Other halogens follow this same pattern, with chlorine as Cl2, bromine as Br2, iodine as I2, and astatine as At2. The subscript indicates the number of atoms of an element in a compound; in this case, two.
Electron dot diagrams help explain why two halogen atoms combine to form a molecule. Fluorine provides an example as shown below. Each fluorine atom has 7 valence electrons and needs only one additional electron to achieve a stable noble gas configuration. If two fluorine atoms come close enough together, they can share electrons, as shown in Figure 31. This shared pair of electrons is a covalent bond. By sharing electrons in the form of a bond, each atom gains a total of 8 valence electrons. Both atoms are far more stable with this configuration than if they remained single atoms.
Fill in the blank.
A
bond is formed when two nonmetals share electrons to become stable.
answer :
covalent
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1.3 Group properties |
