If a substance is impure, not only is the melting range broad more than 2.5°c, but the top of the range is below that of the true melting point. how?

A pure substance will have a melting point that is generally within a 1 °C range of the literature melting point of that substance. An impure substance will typically have a broad melting point range and it will also be at a lower temperature than the literature melting point. We call this a melting-point depression.

A pure crystalline substance will have the particles packed in repeating patterns and these forces hold the crystals together. In an impure substance, the impurities disrupt these forces holding the solid together, therefore, requiring less energy to melt the portion of the solid containing the impurities. Less energy required results in a lower melting point.

There is one s orbital, and there are three p orbitals, five d orbitals, and seven f orbitals. thus, the answer is b. do not confuse the number of orbitals in a subshell with the number of electrons the subshell can hold. each orbital can hold two electrons, so the capacity of an nf subshell is 14 electrons.

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