Structure of Matter (15%) (9 Items) Sample Test Prep Questions 8 th Grade (3a) Structure of Matter Students know the structure of the atom and know it is composed of protons, neutrons and electrons. Summary: Shortly after British physicist Ernest Rutherford inferred the existence of atomic nuclei, the general idea emerged that atoms are mostly empty space with a tiny, massive nucleus at the center containing positively charged electrons and neutral neutrons. This nucleus is surrounded by tiny, negatively charged electrons, each with about 1/1200 the mass of a proton or neutron. Niels Bohr developed a model of the hydrogen atom to explain its visible spectrum. However, Bohr s solar model of the atom is oversimplified. Rather than try to describe how the electrons in an atom are moving, help students develop a model of the atom in which each electron has definite energy. Students should know that the energy of each electron in an atom keeps it in motion around the positive nucleus to which it is attracted. The structure of multielectron atoms is understood in terms of electrons filling energy levels that define orbitals. Utah State Released Questions Which is the smallest particle? A. atom B. molecule C. compound D. solid Correct Answer: A atom Tennessee Released Question Which of these belongs in the outermost shell (energy level) of an atom? A electrons B protons C neutrons D photons Answer: A electrons
A neutral atom of aluminum-27 contains. A 13 protons and 27 electrons. B. 14 protons and 13 neutrons C. 13 electrons, 13 protons and 14 neutrons D. 13 electrons, 14 protons and 13 neutrons Answer: C. 13 electrons, 13 protons and 14 neutrons The atomic number corresponds to an atom s number of. A. protons B. neutrons C. electrons D. positrons Answer: A. protons What is the electric charge on the neutron? A. -1 B. +1 C. 0 D. +2 Answer: C. 0 A proton has which of the following charges? A. Negative B. Neutral C. Positive D. Magnetic Answer: C. Positive - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
The nucleus of an atom consists of: A. electrons B. neutrons C. protons and neutrons D. protons, neutrons, and electrons Answer: C. protons and neutrons - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Which particles have approximately the same size and mass as each other? A. neutrons and electrons B. electrons and protons C. protons and neutrons D. none- they are all very different in size and mass. Answer: C. protons and neutrons - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Which two particles would be attracted to each other? A. electrons and neutrons B. electrons and protons C. protons and neutrons D. all particles are attracted to each other. Answer: B. electrons and protons According to atomic theory, electrons are usually found: A. in the atomic nucleus B. outside the nucleus, yet very near it because they are attracted to the protons. C. Outside the nucleus and often far from it most of an atom s volume is its electron cloud. D. Either in the nucleus or around it electrons are readily found anywhere in an atom. Answer: C. Outside the nucleus and often far from it most of an atom s volume is its electron cloud.
8 th Grade (3b) Structure of Matter Students know that compounds are formed by combining two or more different elements and that compounds have properties that are different from their constituent elements. Summary: The word combining implies bonding. Understanding the concepts of ionic and covalent bonding helps explain why some elements combine to form compounds and some do not. Atoms of different elements combine to form compounds; a compound may, and usually does, have chemical characteristics and physical properties that are different from those of its constituent elements. Examples and generalizations may be drawn from ionic compounds formed of metals and nonmetals and covalently bonded, organic compounds formed from carbon and other elements. Instruction in this standard will help students understand that compounds are collections of two or more different kinds of atoms that are bonded together. Knowing exactly how the atoms are organized to form a molecule is not essential. Which of these is a compound? A Na B H 2 C NaCl D Cl 2 Answer: C NaCl Tennessee Released Question A substance made up of two or more elements that have been chemically combined is called. A an atom B a compound C an element D a mixture Answer: B a compound Which of the following gases is a compound? A ozone (O 3 ) B oxygen (O 2 ) C methane (CH 4 ) D nitrogen (N 2 )
Answer: C methane (CH 4 ) Which of the following materials is composed of only one kind of atom? A Water B Helium C Air D Sugar Answer: B Water 8 th Grade (3c) Structure of Matter Students know atoms and molecules form solids by building up repeating patterns, such as the crystal structure of NaCl or long-chain polymers. Summary: Crystals of table salt, the compound NaCl, have a regular, cubic structure in which sodium (Na + ) ions alternate with chlorine (Cl - ) ions in three-dimensional array with the atoms at the corner of cubes forming the lattice. In organic polymers, the carbon, hydrogen, sometimes oxygen, and nitrogen atoms combine to form long, repetitive, string-like molecules. The shape of a molecule is important to its chemical and physical properties. 8 th Grade (3d) Structure of Matter Students know the states of matter (solid, liquid, gas) depend on molecular motion. Summary: All atoms, and subsequently all molecules, are in constant motion. For any given substance the relative freedom of motion of its atoms or molecules increases from solids to liquids to gases. When a thermometer is inserted into a substance and the temperature is measured, the average atomic or molecular energy of motion is being measured. The state of matter of a given substance therefore depends on the balance between the internal forces that would restrain the motion of the atoms or molecules and the random motions that are in opposition to those restraints. The change in phases is evidence of various degrees of atomic and molecular motion. The conditions of temperature and pressure under which most material change from solid to liquid to vapor (gas) or gas to plasma have been measured. Chemistry handbooks contain the melting points (or freezing points) and boiling points (or condensation temperatures) of most materials usually under one atmosphere pressure. If the pressure is
not one atmosphere, those temperatures change. Some substances have more than one stable solid phase at room temperature. Kansas Released Test Item Samantha s mom dropped an ice cube on the kitchen counter. Samantha noticed later that there was a puddle of water where the ice cube had been. What happened to the water particles? A The particles warmed and spread further apart. B The particles warmed and moved closer together. C The particles cooled and spread further apart. D The particles cooled and moved closer together Answer: A The particles warmed and spread further apart. Oregon Released Question A student pours himself a glass with ice in it. Identify which objects are solid, liquid and gas. A. The cola is the solid, the ice is the liquid, and the bubbles are the gas. B. The ice is the solid, the bubbles are the liquid, and the cola is the gas. C. The bubbles are the solids, the cola is the liquid and the ice is the gas. D. The ice is the solid, the cola is the liquid, and the bubbles are the gas. Answer: D. The ice is the solid, the cola is the liquid, and the bubbles are the gas. Oregon Released Question Which of the following BEST describes how most substances change from a solid to a liquid state? A. Molecules move closer together. B. Molecules move faster apart. C. Molecules lose energy. D. Molecules slow down. Answer: B. Molecules move faster apart.
8 th Grade (3e) Structure of Matter Students know that in solids the atoms are closely locked in position and can only vibrate; in liquids the atoms and molecules are more loosely connected and can collide with and move past one another; and in gases the atoms and molecules are free to move independently, colliding frequently. Summary: The atoms or molecules of a solid form a pattern that minimizes the structural energy of the solid consistent with the way in which the atoms or molecules attract at long distances but repel at short distances. The atoms or molecules vibrate about their equilibrium positions in this pattern. When raised above the melting temperature, the atoms or molecules acquire enough energy to slide past one another so that the material, now a liquid, can flow; the density of the liquid remains very close to that of a solid, demonstrating that in a solid or a liquid the atoms stay at about the same average distance. If a single atom or molecule acquires enough energy, however, it can pull away from its neighbors and escape to become a molecule of gas. Gas molecules move about freely and collide randomly with the walls of a container and with each other. The distance between molecules in a gas is much larger than that in a solid or a liquid and this point may be emphasized when students study density. The particles that are bound together the tightest are found in a A. gas B. liquid C. solid D. mixture Correct Answer: C solid Tennessee Released Question Which of the following physical state has particles that vibrate in place and do not move past their neighbors? A gas B liquid C plasma D solid Answer: D solid
What happens to particles of liquid water when the water is heated? A. No change takes place. B. They speed up and stay in the same place. C. They speed up and begin to slide past each other. D. They slow down. Correct Answer: C. They speed up and begin to slide past each other. Which of the following physical states has particles that move very fast and travel as far apart as they can? A. gas B. liquid C. molecule D. solid Correct Answer: A gas Which of the following physical states has particles that move to take the shape of whatever container they are in? A. gas B. liquid C. molecule D. solid Correct Answer: B liquid Which of the following ways are solids and gases alike? A. Both have particles that move very fast. B. Both have particles that move very slow. C. Both are made of particles. D. Both have particles that are very close together. Correct Answer: C Both are made of particles.
Gases are much more compressible than liquids. According to the particle model of matter, gases are more easily compressed into smaller volumes because the particles in gases are. A. smaller B. more active C. farther apart D. filled with air Answer: C. farther apart Beaker Temperature in Celsius Time until mixed A 3 degrees 3 minutes 45 seconds B 20 degrees 2 minutes 10 seconds C 90 degrees 1 minute 15 seconds Students conducted an experiment testing the time it takes food coloring to mix with water. The results of the experiment are summarized in the table above. Which of the following best explains the results: A. The coloring mixed faster in A because the molecules in cold water move faster. B. The coloring mixed faster in C because the molecules in hot water move faster. C. The coloring mixed slower in A because the molecules in cold water move faster. D. The coloring mixed slower in C because the molecules in cold water move slower. Correct Answer: B. The coloring mixed faster in C because the molecules in hot water move faster. 8 th Grade (3f) Structure of Matter Students know how to use the periodic table to identify elements in single compounds. Summary: The periodic table of elements is arranged horizontally in order of increasing atomic number (number of protons) and vertically in columns of elements with similar chemical properties. Students should learn to use the periodic table as a quick reference for associating the name and symbol of an element in compounds and ions. They should
be able to find the atomic number and atomic weight of the element listed on the table. The periodic table is both a tool and an organized arrangement of the elements that reveals the underlying atomic structures of the atoms. This standard focuses on the table as a tool. Students should be encouraged to refer to the periodic table as they study the properties of matter and learn about the atomic model. Which of the following lists the elements in order, from those having the least protons to those having the most protons in the atoms? A. O,N,B,Li B. Na,S,Al,Cl C. O,S,Se,Te D. Rb,K,Na,Li Answer: C. O,S,Se,Te 5 B Boron 10.811 13 Al Aluminum 26.9815 6 C Carbon 12.011 14 Si Silicon 28.0855 7 N Nitrogen 14.0067 15 P Phosphorus 30.97376 Which of these elements has an atomic number of 14? A. N B. Al C. Si D. P Answer C. Si
5 B Boron 10.811 13 Al Aluminum 26.982 6 C Carbon 12.011 14 Si Silicon 28.086 7 N Nitrogen 14.007 15 P Phosphorous 30.974 Which of these elements has the greatest average atomic mass? A B B C C N D Al Answer: D Al An element is determined by the number of: A. atoms B. electrons C. neutrons D. protons Answer: protons