There are two types of rocks that make up the continental crust "sedimentary and metamorphic rocks." Sedimentary rocks are formed with pressure and compaction, and metamorphic rocks are made with heat and pressure. The earth's crust itself is made up of sedimentary rocks because they are mainly found a little under earths crust same goes with metamorphic rocks.
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Answer:
The nonmetals in Groups 15, 16, and 17 form ions with charges of 3-, 2-, and 1-, respectively.
Explanation:
The elements of Group 18 (the noble gases) have a complete valence shell of eight electrons.
It is <em>easier</em> for the elements of Groups 15 to 17 <em>to</em> <em>gain</em> three, two, or one electron(s) to get a complete valence shell <em>than it is to lose</em> five, six, or seven valence electrons.
Thus, they form <em>negative ions</em> with charges of 3-, 2-, and 1-, respectively.
The charges <em>do not correspond</em> to the Group numbers of 15 to 17 or the old (pre-1990) Group numbers of 5A to 7A.
