2. Atoms & Elements

Four of the boxes in the following periodic table are colored. Which of these are metals and which are nonmetals?

Classify these elements as metals, nonmetals, or semimetals.

Examine Figure 2.3, The periodic table. (f) Classify the following three elements as metals, nonmet-als, or semimetals: Mo, Br, Si.

Discussing this chapter, a classmate says, 'Since elements that form cations are metals and elements that form anions are nonmetals, elements that do not form ions are metalloids.' Do you agree or disagree?

Where in the periodic table are the metallic elements found? Where are the nonmetallic elements found?

What is a semimetal, and where in the periodic table are semimetals found?

Classify the following elements as metals, nonmetals, or semimetals: (a) Ti (b) Te (c) Se (d) Sc (e) Si

Classify the following elements as metals, nonmetals, or semimetals: (a) Ar (b) Sb (c) Mo (d) Cl (e) N (f) Mg

Write the symbol for each element and classify it as a metal, nonmetal, or metalloid. a. gold b. fluorine c. sodium d. tin e. argon

At room temperature, a certain element is found to be a soft, silver-colored solid that reacts violently with water and is a good conductor of electricity. Is the element likely to be a metal, a nonmetal, or a semimetal?

At room temperature, a certain element is found to be a shiny, silver-colored solid that is a poor conductor of electricity. When a sample of the element is hit with a hammer, it shatters. Is the element likely to be a metal, a nonmetal, or a semimetal?

At room temperature, a certain element is yellow crystalline solid. It does not conduct electricity and when hit with a hammer, it shatters. Is the element likely to be a metal, a nonmetal, or a semimetal?

At room temperature, a certain element is a colorless, unre-active gas. Is the element likely to be a metal, a nonmetal, or a semimetal?

Little is known about the properties of astatine, At, because of its rarity and high radioactivity. Nevertheless, it is possible for us to make many predictions about its properties. (a) Do you expect the element to be a gas, liquid, or solid at room temperature? Explain.

Element X reacts with element Y to give a product containing X3+ ions and Y2-ions. (b) Is element Y likely to be a metal or a nonmetal? Explain.

Element X reacts with element Y to give a product containing X3+ ions and Y2-ions. (a) Is element X likely to be a metal or a nonmetal? Explain.

A historian discovers a nineteenth-century notebook in which some observations, dated 1822, were recorded on a substance thought to be a new element. Here are some of the data recorded in the notebook: 'Ductile, silver-white, metallic looking. Softer than lead. Unaffected by water. Stable in air. Melting point: 153 °C. Density: 7.3 g>cm3. Electrical conductivity: 20% that of copper. Hardness: About 1% as hard as iron. When 4.20 g of the unknown is heated in an excess of oxygen, 5.08 g of a white solid is formed. The solid could be sublimed by heating to over 800 °C.' (a) Using information in the text and the CRC Handbook of Chemistry and Physics, and making allowances for possible variations in numbers from current values, identify the element reported.

Classify each element as a metal, nonmetal, or semimetal.