2Question 1:If you know that an element is a solid at room temperature, do you have enough data to classify the element as a metal, metalloid, or nonmetal? If you know that the element is a gas at room temperature, do you have enough data? Explain your answers.
3Question 1: AnswerThere is not enough data for the solid because solids at room temperature can be metals, nonmetals, or metalloids. There is enough data for the gas because there are no gaseous metals or metalloids at room temperature.
4Question 2:An element on the periodic table has two naturally occurring isotopes. One isotope has an atomic mass of about 10 amu. The other isotope has an atomic mass of about 11 amu. What is the name of this element?
5Boron, with an atomic mass of 10.81. Question 2: AnswerBoron, with an atomic mass of
6Question 3:How many valence electrons would an element with atomic number 113 have?
26Question 12:Based on the content of most fertilizers, name two elements other than carbon that are found in compounds in plants.
27Nitrogen and Phosphorus. Question 12: AnswerNitrogen and Phosphorus.
28(Hint: Refer to the discussion on page 149.) Question 13:Explain how the amount of a trace element an organism is exposed to affects the element’s ability to help or harm an organism. Use the example of selenium.(Hint: Refer to the discussion on page 149.)
29Question 13: AnswerAn element that is helpful in small quantities may be harmful when present in larger quantities. For example, trace amounts of selenium help maintain the immune system, but larger amounts can cause nerve damage.
30Question 14:Sometimes old books fall apart when they are stored in air. Use what you know about the reactivity of elements to propose a way that old books could be kept from falling apart.
31The books would not fall apart if stored in a noble-gas atmosphere. Question 14: AnswerThe books would not fall apart if stored in a noble-gas atmosphere.
32Question 15:Explain how a calendar is similar to a periodic table and how is it different?
33Question 15: AnswerThere is a repeating pattern of days and months on a calendar. However, Tuesdays do not necessarily have a different set of properties from Thursdays and there are no trends among Tuesdays equivalent to the trends in atomic mass or reactivity within a group in the periodic table.
34Question 16:When corn plants have yellow leaves, it is a sign that the plants lack an essential element. Which element must be added to the soil to produce leaves with a healthy green color?
35Question 16: AnswerMagnesium is required to produce chlorophyll, the green pigment in plants.
36Question 17:You write for a newsletter that has a feature called Element of the Month. It is your turn to write the feature. Pick an element that you think is worthy of attention. Write a brief essay and suggest a photo to be used with your feature.
37Question 17: AnswerThe essays should contain accurate information and make a reasonable argument for the value of the element.