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Honors Chemistry Periodic Table Review 1. Define periodic trend. A regular repeating pattern in atomic properties based on an element’s position on the periodic table 2. Identify each of the following elements as a metal, nonmetal, or metalloid. a. Fluorine-‐nonmetal b. Germanium-‐metalloid c. Zinc-‐metal d. Phosphorus-‐nonmetal e. Lithium-‐metal 3. Give an example element for each category. a. Noble gas-‐ He, Ne, Ar, Kr, Rn, Xe b. Halogen-‐ Cl, Br, I, F, At c. Alkali metal-‐ any IA element d. Alkaline earth – any IIA element e. Representative element-‐ any s or p block element f. Transition element-‐ any d-‐block element 4. What trend in atomic radius do you see as you go down a group /family on the periodic table? What factors are responsible for this trend? Atomic radius increases. Energy levels are being added which increases e-‐e repulsions and shielding. 5. What trend in atomic radius do you observe as you travel from left to right across a period? What factors are responsible for this trend? Atomic radius decreases. No additional energy levels are being added but the number of protons and electrons increases, thus there is an increase in effective nuclear charge which draws the valence electrons in closer to the nucleus. 6. Circle the atom in each pair that has the largest atomic radius. a) Al or B b) S or O c) Br or Cl d) Na or Al e) O or F f) Mg or Ca 7. For each of the following sets of atoms, rank the atoms from smallest to largest with respect to atomic radius. a. Li, C, F -‐ F, C, Li b. Li, Na, K-‐ Li, Na, K c. Ge, P, O-‐ O, P, Ge d. C, N, Al – N, C, Al e. Al, Cl, Ga –Cl, Al, Ga Honors Chemistry Periodic Table Review 8. For each of the following sets of ions rank them from smallest to largest ionic radius, a. Mg2+, Si4+, S2-‐ -‐ Si4+, Mg2+, S2-‐ b. Mg2+, Ca2+, Ba2+ -‐ same c. F-‐, Cl-‐, Br-‐-‐ same d. Ba2+, Cu2+, Zn2+ -‐Zn2+, Cu2+, Ba2+ e. Si4-‐, P3-‐, O2—O2-‐, P3-‐, Si4-‐ 9. Define ionization energy. Ionization energy is the amount of energy needed to remove an electron from a gaseous atom or ion in its ground state. 10. Examine the first and second ionization energies for sodium and magnesium. Why is there such a large increase in sodium’s second ionization energy relative to magnesium’s second ionization energy? Element 1st Ionization Energy 2nd Ionization Energy Na 496 kJ/mol 4563 kJ/mol Mg 736 kJ/mol 1450 kJ/mol Na+ is a noble gas configuration. Removing an electron from Na+ disrupts the stable octet. Mg+ is not yet an octet. Removing a second electron from Mg results in an octet but is not disrupting an existing octet. Therefore it takes less energy to remove magnesium’s second electron than it does to remove sodium’s second electron. 11. What trend in ionization energy do you see as you go down a group /family on the periodic table? What factors are responsible for this trend? Ionization energy decreases down a group. Energy levels are being added which results in more shielding by the core electrons and more electron-‐ electron repulsions. The valance electrons are further from the nucleus and are held with less force resulting in lower ionization energies. 12. What trend in ionization energy do you observe as you travel from left to right across a period? What factors are responsible for this trend? Ionization energy increases. No new energy levels are being added, however protons and electrons are. This results in a greater effective nuclear charge which pulls the valence electrons in closer to the nucleus and also results in a greater force of attraction between the valence electrons and the nucleus. Honors Chemistry Periodic Table Review 13. Circle the atom in each pair that has the greater ionization energy. a) Li or Be d) Ca or Ba b) Na or K e) P or Ar c) Cl or Si f) Li or K 14. For each of the following sets of atoms, rank them from lowest to highest ionization energy. a. Mg, Si, S -‐same b. Mg, Ca, Ba – Ba, Ca, Mg c. F, Cl, Br – Br, Cl, F 15. Define electronegativity. Electronegativity is the ability of an atom to attract shared electrons in a bond. 16. What trend in electronegativity do you see as you go down a group /family on the periodic table? What factors are responsible for this trend? Electronegativity decreases. Atoms are larger, more shielding, more e-‐e repulsion, valence electrons held with less force-‐ all of these factors make it difficult to attract additional electrons. 17. What trend in electronegativity do you observe as you travel from left to right across a period? What factors are responsible for this trend? Electronegativity increases. The atoms are smaller due to the increase in effective nuclear charge. The valence electrons are held with more force making it easier for the atom to attract the bonded electrons as well. 18. Circle the atom in each pair that has the greater electronegativity. a) Cu or Ga b) Li or O c) Cl or S d) Br or As e) Ba or Sr f) O or S 19. For each of the following sets of atoms, rank them from lowest to highest electronegativity. a. Li, C, N -‐same b. C, O, Ne-‐ Ne C, O c. Si, P, O-‐ same d. K, Mg, P-‐same e. S, F, He-‐ He, S, F Honors Chemistry Periodic Table Review 20. Define electron affinity. Electron affinity refers to the energy released when a gaseous atom in its ground state gains an electron. 21. What is the difference between electron affinity and ionization energy? Ionization energy-‐ losing an electron, energy is put into the system (+) Electron affinity-‐ gaining an electron, energy is usually released (-‐) 22. Rank the members of the following isoelectronic series in order of decreasing atomic radius. Justify your ranking. Sr2+, Kr, Se2-‐, Br-‐, Rb+ Sr2+, Rb+, Kr, Br-‐, Se2-‐ Worksheet from: cyfair3.schoolwires.net/195520511193516957/lib/195520511193516957/ _Files/pertrends0001.pdf
