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One characteristic of a scientific theory is that it can never be proved The variable that is observed during an experiment is called what type of variable? Responding . Which of the following is NOT an example of matter? Heat All of the following are physical properties of matter EXCEPT ___. Ability to rust Which of the following is NOT a physical property of water? It is composed of hydrogen in oxygen. Which state of matter expands when heated and is easy to compress? Gas Which state of matter is characterized by having an indefinite shape, but a def. volume? Liquid Which of the following is a physical change? Evaporation Which of the following is a heterogeneous mixture? Soil, steel, salt water, air soil Separating a solid from a liquid by evaporating a liquid is called distillation What is one difference between a mixture and a compound? A compound can only be separated into components by chemical means. Which of the following is a chemical property? Ability to react with oxygen, freezing point, hardness, color Ability to react with oxygen What must occur for a change to be a chemical reaction? There must be a change in chemical properties. Which of the following does not involve a physical change? Mixing, grinding, decomposing, melting mixing A chemical change occurs when a piece of wood ____. Decays When paper turns yellow brown upon exposure to sun light, what type of change is taking place? Chemical change Which of the following does NOT indicate that a chemical change may have taken place? Physical change Which of the following does not indicate that a chemical change may have taken place? Fracture formation When an iron nail is ground into powder, its mass stays the same The expression of 5008 km in scientific notation is 5.008 x 10 3 km The closeness of a measurement to its true value is a measure of its accuracy When a test instrument is calibrated, does its accuracy, precision or reliability improve? All of the above Three different people weigh a standard mass of 2.00 g on the same balance. Each person obtains a reading of 7.32g for a standard. These results imply that the balance used was precise How many significant figures are in the measurement 0.0034 kg? two How many significant figures are in the measurement 40, 5000 mg? five Express the sum of 7.68 m and 5.0 m using the correct number of significant digits. 12.7 m Express the sum of 7.68m and 5.0 mm using the correct number of significant digits. 11 mm What is the measurement of 1042 L rounded off to two significant digits? 1.1 x 103 When multiplying and dividing measured quantities, the number of significant figures in the result should be equal to the number of significant figures in the least precise measurement . What is the volume of a salt crystal measuring 2.44 x 10-2 by 1.4 x 10-3 by 8.4 x 10-3. 2.9 x 10 m Which of the following equalities is not correct? 10 kg = 1 g, 1000mm = 1m, 1cm3 = 1mL, 100 cg = 1 g 10 kg = 1 g What is the volume of a 45.6 g of silver if the density of silver is10.5 g/mL? 4.34 mL If the temp of a piece of steel decreases, what happens to its density? Density increases AS the density of a substance increases, the volume of a given mass of that substance... decreases Bohrs model of the atom, where ate the electrons and protons located? Electrons move around the protons, which are at center of atom In the Bohr model of the atom, an electron in an orbit has a fixed energy How does the energy of an electron change when the electron moves closer to the nucleus decreases principal quantum number indicates what property of an electron? Energy level How many energy sublevels r there in the second principle energy level? 2 What is the maximum number of f orbitals in an single energy level in an atom? 7 . What is the maximum number of d orbialts in a single energy level? 5 What is the maximum number of orbitals in the p subshell? 3 What is the maximum number of electrons in the second principle energy level? 8 When an electron moves from a lower energy level to a higher energy level, the electron absorbs a quantum of energy the shape (not the size) of an electron cloud is determined by the electrons energy sublevel The letter "p" in the symbol 4p3 indicates the orbital shape . If the spin of one electron in a orbital is clockwise, what is the spin of the other electron in that orbital? Counterclockwise What types of atomic orbitals are in the third principal energy level? S, p, d only What is the next atomic orbital in the series 1s 2s 2p 3s 3p 4s What is the number of electrons in the outermost energy level of an oxygen atom? 6 If three electrons are available to fill three empty 2p orbitals, how will they be distributed? One electron in each orbital How man unpaired electrons are there in a sulfur atom (atomic # 16) 2 How many half filled orbitals are there in a bromine atom? 1 Stable electron configurations are likely to contain filled energy sublevels Which electron configuration of the 4f energy sublevel is the most stable? 4f14 Which color of visible light has the shortest wavelength? Violet Which of the following electromagnetic waves have the highest frequencies? Gamma rays The light given off by an electric discharge through sodium vapor is an emission spectrum Emission of light from an atom occurs when an electron drops from a higher to a lower energy level As changes in energy levels of an electron increase, the frequencies of atomic line spectra they emit increase the atomic emission spectra of a sodium atom on earth and a sodium atom on the sun would be the same Which of the following quantum leaps would be associated with the greates energy of emitted light? N =5 to n = 1 What are quanta of light called photons Bhors model could only explain the spectra of which types of atoms single atoms with more than one electron The quantum mechanical model of the atom involves the probability of finding an electron in a certain position in an s orbital, the probability of finding an electron a particular distance from the nucleus does not depend on direction with respect to the nucleus what is the number of electrons in the valence energy level of an oxygen atom? 6 how many unpaired valence electrons are in an oxygen atom? 2 How many unpaired valence electrons are in a fluorine atom? 1 what is the basis for exceptions to the Aufbau? Filled and half filled energy subshells are more stable than partially filled energy sublevels. What element has the electron config 1s22s22p63s23p2? Silicon Which of the following electron configs is most likely to result in an element that is relatively inactive? A filled highest occupied principal energy level which subatomic particle plays the greatest part in determining the properties of an element electron how does the atomic radius change from top to bottom in a group in the periodic table? Tends to decrease how does the atomic radius change from left to right across a period? Decrease atomic size generally decreases as you move from top to bottom within a group what element in the second period has the largest atomic radius? Lithium which of the following elements has the largest atomic radius? Chlorine which of the following is true about ions? Cations form when an atom loses electrons which of the following statements is not true about ions? When a cation forms, more electrons are transferred to it Which of the following elements has the smallest ionic radius? Li What is the energy required to remove an electron from an atom in the gaseous state called? Ionization energy Which of the following factors contributes to the decrease in ionization energy within a group on the periodic table as the atomic number increases? Increase in atomic size which of the following elements has the smallest first ionization energy? Potassium which of the statements correctly compares the relative size of an ion to its neutral atom? The radius of an anion is greater than the radius of its general atom. use a period table - choose element you would expect to have the largest ionization energy He, C, Si, Ca He How many valence electrons are in an atom of phosphorous? 5 Valence electrons in Magnesium? 2 Valence electrons in helium? 2 Valence electrons in silicon? 4 What is the name given to the electrons in the highest occupied principal energy level of an atom? Valence electrons The octet rule states that, in chem. Compounds atoms tend to have the electron config of a noble gas How many electrons does barium have to give up to achieve noble gas config? 2 What is the formula of the ion formed when potassium achieves noble-gas electron config? K+ How many electrons does nitrogen gain in order to achieve a noble gas config? 3 What is the formula of the ion formed when phosphorus achieves a noble gas electron config? P3- How does oxygen obey the octet rule when forming compounds? Gains electrons The electron config of a fluoride ion F- is the same as that of a neon atom Which occurs in an ionic bond? Oppositely charged ions attract A compound held together by ionic bonds is called a salt Which is true about an ionic compound? It is held together by ionic bonds Which of the following pairs of elements is most likely to form an ionic compound? Magnesium and fluorine Which of the following is not a characteristic of most ionic compounds? They have low melting points Which of these elements does not exist as a diatomic molecule? Ne How do atoms achieve noble gas electron configurations in single covalent bonds? Two atoms share two electrons Which of the following elements can form diatomic molecules held together by triple covalent bonds nitrogen Which of the following is the name given to the pairs of valence electrons that do not participate in bonding in diatomic oxygen molecules? Nonbonding pair Which of the following diatomic molecules is joined by a double covalent bond? O2 A molecule with a single covalent bond is Cl2 How many electrons can occupy a single molecular orbital? 2 Molecular orbital theory is based upon which of the following models of the atom? Quantum mechanical How is a pair of molecular orbitals formed? By the overlap of two atomic orbitals from different atoms Which of the following atoms acquires the most negative charge in a covalent bond with hydrogen? O A bond formed between a silicon atom and an oxygen atom is likely to be polar covalent Which of the following covalent bonds is the most polar? H-F