The melting points of the oxides of the third-period elements are given in parentheses: na2o (1275°c), mgo (2800°c), al2o3 (2045°c), sio2 (1610°c), p4o10 (580°c), so3 (16.8°c), cl2o7 (91.5°c). classify these solids in terms of crystal types. a) na2o: ionic covalent molecular metallicb) mgo: ionic covalent molecular metallicc) al2o3: ionic covalent molecular metallicd) sio2: ionic covalent molecular metallice) p4o10: ionic covalent molecular metallicf) so3: ionic covalent molecular metallicg) cl2o7: ionic covalent molecular metallic

A) Ionic, B) Ionic, C) Ionic, D) Covalent, E) Molecular, F) Covalent, G) Covalent

Explanation:

The ionic crystals are formed when a metal loses electrons, forming a cation, and a nonmetal gains those electrons, forming an anion. The covalent crystals are those in that two nonmetals share pairs of electrons, and when they are large, it's called a molecular crystal. The metallic crystals are those formed by metals only.

A) Na is metal and O is a nonmetal, so it's ionic.

B) Mg is metal and O is a nonmetal, so it's ionic.

C) Al is metal and O is a nonmetal, so it's ionic.

D) Both Si and O are nonmetals, so it's covalent.

E) Both P and O are nonmetals, but the crystal has a large number of atoms, so it's molecular.

F) Both S and O are nonmetals, so it's covalent.

G) Both Cl and O are nonmetals, so it's covalent.

answer: c.

explanation:

why is cellular respiration important for homeostasis?

it changes food into energy that the organism can use.

which of the following is most likely to happen if a cell is not able to divide?

the cell will not be replaced when it is damaged.

explanation: