Periodic Table Worksheet 3 Answers

Honors Chemistry Name: _____ Worksheet 3-3 Periodic Trends 1. Discuss the importance of Mendeleev's periodic law. Mendeleev was the 1st to arrange elements on the table. He did so by mass, but did not apply ble periodic law, which coincides with each element as a metal, metalloid, or nonmetal. 2. Identify each element as a metal, metalloid, or nonmetal. a) fluorine NM b) germanium M/Metalloid c) zinc M d) phosphorus NM e) lithium M 3. Give two examples of elements for each category. a) noble gases Kr, Xe (Group 8A) b) halogens Br, F (Group 7A) c) alkali metals Li, Na (Group 1A) d) alkaline earth metals Mg, Ca (Group 2A) 4. What trend in atomic radius do you see as you go down a group/family on the periodic table? Atomic radius increases as you go down a group. What causes this trend? more substance present (e-p+ n° orbitals) 5. What trend in atomic radius do you see as you go across a period/row on the periodic table? less core charge, so the e- aren't held as tightly (less compact) What causes this trend? 6. Circle the atom in each pair that has the largest atomic radius. a) Na Al b) O F c) Mg Ca 7. Define ionization energy. energy required to remove an electron from the valence shell of an atom. 8. Is it easier to form a positive ion with an element that has a high ionization energy or an element that has a low ionization energy? Explain.   It requires less energy to remove an electron which makes it easier to form a positive ion. Na has only one valence electron, while Mg has 2. To become more stable (like noble gases) elements will gain or lose e- to create a full energy shell. 9. Use the concept of ionization energy to explain why sodium forms a 1+ ion (Na+) but magnesium forms a 2+ ion (Mg²⁺). 10. What trend in ionization energy do you see as you go down a group/family on the periodic table? What causes this trend?   Decreases, as the atom gets larger, there is more shielding, which would require less energy to remove an electron. Honors Chemistry 11. What trend in ionization energy do you see as you go across a period/row on the periodic table? What causes this trend?   Increases as you go right The more core charge, the closer to the center (nucleus) + also the closer to 8e- the more energy required to remove an electron. 12. Circle the atom in each pair that has the greater ionization energy. a) Li Be b) Na Ar c) Cl Si d) Ba Ca e) Ar P 13. Define electronegativity: "attractiveness": the tendency of an atom to attract e- to itself. 14. What trend in electronegativity do you see as you go down a group/family on the periodic table? What causes this trend? Decreases (same as   IE #10) 15. What trend in electronegativity do you see as you go across a period/row on the periodic table? What causes this trend? Increases as you go right (same as IE   #11) EXCLUDES NOBLE GASES 16. Circle the atom in each pair that has the greater electronegativity. a) Ca Ga b) Li O c) Cl S d) Br As e) Ba Sr f) O S Define electron affinity. What trend in electron affinity do you see as you go down a group/family on the periodic table? What causes this trend? What trend in electron affinity do you see as you go across a period/row on the periodic table? What causes this trend?