GRE Subject Test: Chemistry : Non-Metals
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Example Questions
Example Question #1 : General Chemistry
Which of the following features is characteristic of nonmetals?
They have higher melting points than metals
They form negative ions
They form ionic bonds with each other
They are easily stretched
They form negative ions
Nonmetals are generally brittle elements that have lower melting points than metals. They also form covalent bonds with one another due to minimal difference in electronegativity between nonmetal elements.
Nonmetals most frequently form negative ions in solution, called anions. In contrast, metals most frequently form positive ions in solution, known as cations.
Example Question #2 : General Chemistry
A researcher has substance X and substance Y. After performing several tests, he finds out that substance X is a metal oxide and substance Y is a non-metal oxide. is What will the researcher observe when he measures the pH of each oxide in aqueous solutions of equal concentrations?
Substance Y will have a lower pH because non-metals produce acidic oxides
The pH will be 7 because metal and non-metal oxides are products of a neutralization reaction
Both oxides will have a pH greater than 7
Substance X will have a lower pH because metals produce acidic oxides
Substance Y will have a lower pH because non-metals produce acidic oxides
One of the key distinguishing characteristics of metals and non-metals is the acidity of their oxides. Metal oxides are basic oxides, whereas non-metal oxides are acidic oxides. Remember that acids have low pH (high hydrogen ion concentration), whereas bases have high pH (low hydrogen ion concentration); therefore, non-metal oxides will have the lower pH.
A neutralization reaction is a special type of reaction that occurs between an acid and a base. This type of reaction will produce a pH of 7 if the reacting species are a strong acid and a strong base. Metal and non-metal oxides do not involve acid-base reactions; therefore, neutralization reaction is irrelevant to this question.
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