Regents Chemistry Test Preparation Practice

    Characteristic Trends

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    Base your answers to questions 10 on the information below and on your knowledge of chemistry.

    Radioactive emissions can be detected by a Geiger counter. When radioactive emissions enter the Geiger counter probe, which contains a noble gas such as argon or helium, some of the atoms are ionized. The ionized gas allows for a brief electric current. The current causes the speaker to make a clicking sound. To make sure that the Geiger counter is measuring radiation properly, the device is tested using the radioisotope Cs-137.

    To detect gamma radiation, an aluminum shield can be placed over the probe window, to keep alpha and beta radiation from entering the probe. A diagram that represents the Geiger counter is shown below.

    characteristic-trends fig: chem82019-exam_g13.png

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    Base your answers to questions 11 on the information below and on your knowledge of chemistry.

    Periodic trends are observed in the properties of the elements in Period 3 on the Periodic Table. These elements vary in physical properties, such as phase, and in chemical properties, such as their ability to lose or gain electrons during a chemical reaction.

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    Base your answers to questions 12 on the information below and on your knowledge of chemistry.

    The elements in Group 2 on the Periodic Table can be compared in terms of first ionization energy, electronegativity, and other general properties.

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    Base your answers to questions 14 on the information below and on your knowledge of chemistry.

    Rubidium and iodine have different chemical and physical properties. Some of these properties are shown in the table below.

    identification-of-element fig: chem12018-exam_g14rd047.png

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    Base your answers to questions 15 on the information below and on your knowledge of chemistry.

    Many scientists made observations of the elements that led to the modern Periodic Table. In 1829, Dobereiner found groups of three elements that have similar properties and called each of these groups a triad. Dobereiner noticed a relationship between the atomic masses of the elements in each triad. Triad 1, shown in the table below, consists of sulfur, selenium, and tellurium. The middle element, selenium, has an atomic mass that is close to the sum of the atomic masses of sulfur and tellurium, divided by 2.

    elements-in-the-periodic-table fig: chem82017-exam_g18.png

    The other triads shown in the table below demonstrate the same mathematical relationship.

    elements-in-the-periodic-table fig: chem82017-exam_g17.png

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