Atomos - Chem I - Test 2

Transcription

1 Atomos - Chem I - Test 2 Multiple Choice CIRCLE your choice. 1. His cathode ray-tube experiments led to the discovery of the electron. a. Rutherford b. Thompson c. Chadwick d. Dalton 2. Which of the following is a characteristic of the modern periodic table? a. A group is a horizontal row on the periodic table. b. The elements in each group have similar chemical properties. c. A period is a column on the periodic table. d. The periods contain the representative elements. e. The groups contain the transition elements. 3. The periodic law states that: a. The physical and chemical properties of the elements are functions of their atomic mass b. The periods indicate the number of valence electrons for any given element c. The physical and chemical properties of the elements are functions of their atomic number d. The groups of the table indicate the electron shell where the valence electrons are found. 4. It is as reactive as some metals but is considered a chemical family on its own: a. helium b. metalloids c. diatomic molecules d. hydrogen 5. Dalton s idea that atoms could not be subdivided, created or destroyed was contradicted by: a. the use of radioactive isotopes like carbon-14 c. the Heisenberg Uncertainty Principle b. the periodic table designed by Mendeleev d. the detonation of the atomic bomb 6. The gold foil experiment led to the conclusion that: a. the positive part of the atoms is moving very rapidly. b. the positive charge is distributed throughout the atom. c. electrons were near the nucleus of the atom d. a concentrated positive charge existed somewhere within the atom e. neutrons made up the bulk of the mass of the atom. Consider the following notation: 86Rn - Which statement below is correct? a. this particle contains 86 protons d. this particle contains 220 neutrons b. this particle has a atomic mass of 86 e. all of the above c. this particle has an atomic number of 220 f. A and D only 8. Beryllium and calcium based on their position on the periodic table. a. are less reactive than lithium and potassium c. are less dense than lithium and sodium b. are less reactive than neon and krypton d. have more protons than fluorine and bromine 9. The identity of any given atom/element can definitely and without question be determined by its number of: a. electrons b. neutrons c. protons e. protons + neutrons d. total protons + electrons + neutrons 10. An atom is electrically neutral because: a. neutrons balance the protons and electrons. b. neutrons stabilize the nucleus c. the numbers of protons and electrons are equal. d. the numbers of protons and neutrons are equal in the nucleus 11. The mass of a neutron is: a. about the same as the mass of a proton. b. more than double the mass of a proton. c. about the same mass as an electron d. double the mass of an electron Give the answer to the following in the correct number of significant figures. ( ) + ( ) a b x 10 3 c d e

2 For questions 13-14, use the following list of unknown Atoms : The symbols are arbitrary, pay attention to the numbers A X G Z T Which atom(s) is/are isotopes of an atom with 8 protons and 9 neutrons? a. X b. X and T c. G and Z d. G e. Z 14. Which atom(s) are isotopes of an atom with protons and 8 neutrons? a. A b. X c. A and Z d. X and T e. None The nucleus of an atom has all of the following characteristics EXCEPT that it: a. is positively charged c. contains nearly all of the atom's mass b. is very dense d. contains nearly all of the atom's volume 16. Which of the following statements is true? a. different atoms of the same element cannot have unique chemical or physical properties b. atoms cannot be created, divided or destroyed in ordinary chemical reactions c. atoms can never combine with other atoms d. all atoms are composed of large particles called elements 1. Henry Moseley's work led to the realization that elements with similar properties occurred in a repeating pattern when the elements were arranged in order of increasing: a. atomic mass b. density c. radioactivity d. atomic number e. mass number Complete the following table: Symbol 18 59Mn Atomic Number Name Atomic Mass or Mass Number Protons Electrons Neutrons Check ( ) the appropriate Box (just one) Physical Change Chemical Change Physical Property Chemical Property Exploding Fireworks Gold is formed into a ring The color of a metal Acid is corrosive Water will boil in ABQ at about 93 C

3 Answer the following completely: 21. List five (5) good observations that you could make during a lab that would give you clear evidence that a chemical change had/has occurred. 22. What is the difference between the mass number, and the average atomic mass of an atom? 23. Give an example of a region of the periodic table that acts as a bridge between two other regions. What can this tell you about the properties of the bridging elements? Explain. 24. A cylinder of brass has a mass of 92.5 g and an initial temperature of 89.5 C. It is placed into a calorimeter with 5.2 g (ml) of water at 20.5 C. After gently stirring, the final temperature of the water and metal MIX is 2.4 C. Determine the approximate specific heat of brass.

4 25. Assume that you place two beakers of water out at room temperature (about 20 C). Beaker A contains 50 grams of water at 80 C. Beaker B contains 50 grams of water at 15 C. a. Specifically, how will the temperature of the water change in each beaker? b. For which beaker will this change be complete sooner? Explain. c. For one of the beakers, the change is endothermic. For the other beaker, the change is exothermic. Which beaker is which? Explain. Identify these SPECIFIC parts/section/group of the table Identified by these TOP column numbers 2. Identified by these SIDE row numbers

5 25. Assume that you place two beakers of water out at room temperature (about 20 C). Beaker A contains 50 grams of water at 80 C. Beaker B contains 50 grams of water at 15 C. a. Specifically, how will the temperature of the water change in each beaker? b. For which beaker will this change be complete sooner? Explain. c. For one of the beakers, the change is endothermic. For the other beaker, the change is exothermic. Which beaker is which? Explain. 26. In the table below, write the letter or chemical symbol that fits the following descriptions: a. the halogen in period five b. any lanthanide c. the alkali metal in period four d. the metalloid in period three e. the noble gas in period seven f. the alkaline earth metal in period six g. any transition metal h. the group numbers

6 25. Assume that you place two beakers of water out at room temperature (about 20 C). Beaker A contains 50.0 grams of water at 80 C. Beaker B contains 50.0 grams of water at 15 C. a. Specifically, how will the temperature of the water change in each beaker? b. For which beaker will this change be complete sooner? Why? c. For one of the beakers, the change is endothermic. For the other beaker, the change is exothermic. Which beaker is which? The following figure shows TWO different things: SHADED REGIONS of the table (letters) and FAMILY GOUPS (numbers) of the table. You must distinguish between the two B A 6 C 8 D E 26. In which region are the elements that can generally be found alone in the soil or crust of the Earth? a. 5 b. 2 c. 3 d. 1 e. 1, 9, 5 f. B, D and E 2. Which region are the metalloids? a. A b. B c. C d. D e. E f. 6 g. 2 and In which region are the nonmetals? a. A b. B c. C d. D e. E f. 6, 2 and The metals are in which region? a. 1 b. B c. C d. D e. E f. B, D and E 30. Which family has metals that are low density and so soft that they can be cut with a knife? a. 4 b. 5 c. D d. 9 e. 4 f The transition metals are found in this region: a. 3 b. c. B d. 9 e. 1 f. 9, 5 and The lanthanide series are found in this region: a. 4 b. 2 c. 9 d. 10 e. f. D and E 33. Which family group has the most reactive nonmetals? a. 6 b. 5 c. 8 d. 2 e. C f. D and E 4

7 25. Assume that you place two beakers of water out at room temperature (about 20 o C). Beaker A contains 50 grams of water at 80 o C. Beaker B contains 50 grams of water at 15 o C. a. Specifically, how will the temperature of the water change in each beaker? b. For which beaker will this change be complete sooner? c. For one of the beakers, the change is endothermic. For the other beaker, the change is exothermic. Which beaker is which? Identify these SPECIFIC parts/sections of the table Identified by these TOP column numbers 2. Identified by these SIDE row numbers

8 Calculate the following: 21. A cylinder of brass has a mass of 92.5 g and an initial temperature of 89.5 C. It is placed into a calorimeter with 5.2 g (ml) of water at 20.5 C. After gently stirring, the final temperature of the water and metal MIX is 2.4 C. Determine the approximate specific heat of brass. Answer the following completely: 22. List five (5) good observations that you could make during a lab that would give you clear evidence that a chemical change had/has occurred There are four naturally occurring forms of Iron, Fe, Fe, Fe and Fe. If this is the case, then why is the atomic mass of iron listed as on the periodic table? Explain. 24. Give an example of a region of the periodic table that acts as a bridge between two other regions. What can this tell you about the properties of the bridging elements? Explain.