The Atom -- Test Review

Transcription

1 The Atom -- Test Review 1. In what ways are all atoms similar? In what ways are they different? How do these differences result in different chemical and physical properties? All atoms have a nucleus, protons, electron, and at least one orbital. Different elements always have different number of protons. They usually have different number of neutrons and electrons. Importantly different atoms have different numbers of valence electrons which determines their chemical reactivity (what they will bond to). 2. omplete the table below. When using your periodic table, round mass numbers to the nearest whole number. Element Symbol Atomic Mass Electrons Protons Neutrons Si H r F K Write the full electron configurations for: S 1s 2 2s 2 2p 6 3s 2 3p 4 S 2-1s 2 2s 2 2p 6 3s 2 3p 6 a 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 a 2+ 1s 2 2s 2 2p 6 3s 2 3p 6 4. How many valence electrons does each of the above atoms contain? S = 6, a = 2, S 2- = 8, a 2+ = 8 5. What takes place when a neutral atom becomes a cation? How does this affect the nucleus? A neutral atom must lose an electron to become a cation. This does not change anything in the nucleus as the number of protons is not affected. If you change the number of protons you will have a new element. 6. Describe the ground state and excited state relate of an atom. Draw a diagram to support your explanation. In your drawing you should show an electron in the ground state as closer to the nucleus. When it absorbs energy it moves to a higher energy level, further away from the nucleus. This is the excited state. Eventually it will return to the ground state and will release energy. 7. Why do atoms gain or lose electrons to form ions? To gain an octet (a full outer shell) and become more stable.

2 8. reate a table showing the charge, mass, and location of the electron, neutron, and proton. Particle harge Mass Location Electron -1 1/2000 (very small) Around nucleus Proton +1 1 In nucleus Neutron 0 1 In nucleus 9. A B 14 6 What does each arrow represent? A. mass number B. atom symbol. atomic number How would you name this isotope? arbon omplete the chart below: See and Scientist Description of Model Diagram Democritus J.J. Thomson Matter is made of very small particles called atoms. These particles cannot be broken down any further. Supporting Data: None The Plum Pudding Model: atoms are made up of negative electrons trapped inside a mass with a positive charge. Supporting Data: deflection of stream of negatively charged particles in RT. Bohr Rutherford Sc A B What does each arrow represent? A. Atomic number B. Atomic symbol. Atomic Mass How many neutrons would you expect an atom of Sc to have?

3 DRAFT 01/05 Teacher Resource Periodicity Review PERIODIITY Directions omplete the table by writing the electron configurations, valence electrons, and predicted oxidation number for each atom. Atom Electron onfiguration Valence Electrons Predicted Oxidation Nitrogen 1s 2 2s 2 2p 3 5 N 3- Aluminum 1s 2 2s 2 2p 6 3s 2 3p 1 3 Al 3+ Sodium 1s 2 2s 2 2p 6 3s 1 1 Na + Beryllium 1s 2 2s 2 2 Be 2+ Sulfur 1s 2 2s 2 2p 6 3s 2 3p 4 6 S 2-1. Write the symbol for the element that is located in each of the following positions on the periodic table. a. period 1, group 18 He c. period 4, group 5 V b. period 7, group 2 Ra d. period 3, group 13 Al 2. Atomic radius generally increases within a group and decreases as you move from left to right in a period. Explain this trend. The atomic radius increases in a group because an energy level is added to each element as you move down the group. This extra energy level increases the size of the atom. Nuclear charge increases from left to right in a period. The increased nuclear charge causes the atoms to become more compressed, hence smaller in size. 3. Ionization energy and electronegativity follow opposite trends from atomic radius. Explain what causes these trends to occur. Ionization energy and electronegativity decrease as you move down a group because the electrons are farther from the nucleus due to the extra energy levels added. This causes the electrons to be held to the atom less tightly, making it easier to remove electrons (ionization energy) and harder to attract electrons to the nucleus (electronegativity). As you move across a period, the electrons are more attracted to the nucleus because of an increasing nuclear charge making it harder to remove electrons. 4. What names are given to the following groups on the periodic table? a. group 1 alkali metal b. group 2 alkaline earth metal c. group 17 halogen d. group 18 noble gases e. groups 3-12 transition metal HEMISTRY PERIODIITY 2005 MPS SIENE 97

4 PERIODIITY DRAFT 01/05 5. In the following groups of elements, which element has the largest atomic radius? ircle the correct response. a. F, Be, O b. N, Sb, Bi 6. In the following groups of elements, which element has the lowest electronegativity? ircle the correct response. a. At, l, F b. Br, Mn, K Directions: Use the table and information below to answer the next two items. Group 2 ions reacted with solutions of other salts. If a group 2 cation reacted to form a precipitate, a P was recorded. An S for soluble was recorded if no precipitate formed, RESULTS OF REATING GROUP 2 IONS WITH SALTS Reagent Solutions of Various Salts A B D Ba 2+ P P P P a 2+ S P P S Mg 2+ S P S S Sr 2+ P P P S 7. List the group 2 cations in order of increasing solubility. Ba 2+, Sr 2+, a 2+, Mg What does this data show is the periodic trend associated with solubility? Solubility decreases as you move down the group. Directions: Use the table and information below to answer the next two items. Halogens were reacted with solutions containing halide ions. Data was recorded in the table below. If a reaction occurred, an R was recorded. If no reaction occurred, NR was recorded. Halogen RESULTS OF REATING HALOGENS WITH HALIDE IONS Solution ontaining Halide Ions l - (aq) Br - (aq) I - (aq) l 2 NR R R Br 2 NR NR R NR NR NR NR 9. What is the periodic trend for reactivity according to the data table? Reactivity decreases as you move down the group. 10. What can be inferred about the reactivity of fluorine from this data? Fluorine should be more reactive than any of the other halogens because it is the first element in the group. 98 HEMISTRY PERIODIITY 2005 MPS SIENE

5 DRAFT 01/05 Teacher Resource BR #1: The Undiscovered Element PERIODIITY Assessed Indicators HS4.1 The student will explain that atoms have structure and this structure serves as the basis for the properties of elements and the bonds that they form. HS a HS b HS c HS HS4.1.2.F locate groups/families on the periodic table, including groups 1-18, and the Alkali Metals, Alkaline Earth Metals, Transition Metals, Halogens, Noble Gases, Lanthanide Series, and Actinide Series. describe the properties of the groups/families on the periodic table. locate periods 1-7 on the periodic table. describe how the trends of valence electrons, atomic radius, ionization energy, relative chemical reactivity, and metallic/nonmetallic properties behave in groups 1, 2, and predict chemical and physical properties based on an element s location on the periodic table. Sample Level 4 Response Element 117 would belong to the group known as halogens. It would have seven valence electrons and gain one to become a stable ion. It would have a larger radius than At because it has an extra energy level and would have a low ionization energy and electronegativity because it is so far down on the periodic table. Student anchor papers for this item are needed. Anchor papers are selected from responses written by students that provide examples of each score point, including score point 0 (written response - not a blank paper). It is helpful to have anchor papers that demonstrate the range of each score point (high 3, middle 3, low 3, high 2, middle 2, etc.). Send photocopies of student responses to the Science Office. HEMISTRY PERIODIITY 2005 MPS SIENE 99