Periodic Table: Bell Ringer What does a period and a group refer to on the periodic table? What period and group is Bromine on? What element is on period 5 and group 10? For homework, how did you classify the elements on the periodic table? Periodic Table Metallic Properties Non-metallic Properties History of the Periodic Table Dmitri Mendeleev: • Russian chemists and teacher •When organized elements into groups by similar chemical properties, he observed the periods increasing in atomic mass. • His organization system was successful at predicting undiscovered elements. •Do you observe any inconsistencies with his organization system? History of Periodic Table Henry Moseley: •British Physicists •Observed that when elements were placed in groups by chemical properties, the periods consistently increased by atomic number. •Currently accepted organization system for elements. Bell Ringer: Periodic Table 1. How is the current periodic table arranged? 2. Classify the following properties as metallic or nonmetallic. a. ductile b. low density c. high luster d. insulator 3. What element is on period 3; group 16? 4. Circle the elements below that have similar chemical properties: Carbon (C); Nitrogen (N); Silicon (Si); Boron (B) Organization of Periodic Table Why do elements in the same group have similar chemical properties? Valence Electrons •Electrons in the highest energy level of an element’s atom. •Calculate using short-hand electron configuration. •Determines the chemical reactivity of an element. Periodic Table : Bell Ringer 1. a. What period and group is Aluminum on? b. What element is in period 4; group 2 ? 2. Circle the elements below that have similar chemical properties. Carbon (C), Nitrogen, (N), Silicon (Si), Boron (B) 3. What are valence electrons? 4. Why is it important to know the number of valence electrons an element can have? Short-Hand Electron Configuration •Short -hand configuration targets valence electrons Ex. Sulfur (S): [ Ne] 2s22p4 = 6 valence electrons Valence Electrons Worksheet Key 1. 7 ve2. 5ve3. 2ve4. 5ve5. 2ve6. 8ve7. 1ve8. 2ve9. 2ve10. 6ve- 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. 1ve2ve4ve7ve6ve2ve3ve1ve8ve2ve- Organization of Periodic Table Why do elements in the same group have similar chemical properties? Periodic Table Lab: Valence Electrons Lab grps grp 1 grp 2 veve- grp 3-12 grp 13 veve- grp 14 ve- grp 15 ve- grp 16 ve- grp17 grp18 veve- A B C D What can be concluded from the data table? Periodic Table: Valence Electrons Lab grps grp 1 grp 2 veve- grp 3-12 grp 13 veve- grp 14 ve- grp 15 ve- grp 16 ve- grp17 grp18 veve- A 1 2 2 3 4 5 6 7 8 B 1 2 2 3 4 5 6 7 2 C 1 2 2 3 4 5 6 7 8 D 1 2 2 3 4 5 6 7 8 What can be concluded from the data table? Common Periodic Table Groups Periodic Groups Group # Alkali Metals Valence Electrons 1 ve- • Highly Reactive metals • Only needs to lose 1 ve- to reach STABILITY. Depends on lower energy level that is filled. 2ve- •Reactive •Only needs to lose 2 ve- to reach STABILITY. •Depends on lower energy level that is filled. 1 Alkaline-Earth Metals 2 Transitional Metals 2ve- 3-12 Halogens 17 Chemical Properties •Reactive •Varies in amount of valence electrons lost to reach STABILITY. •Depends on lower energy level that is filled. •Highly Reactive non-metals. •Only needs to gain 1 ve- to reach STABILITY. •Depends on filling up outer energy level. Chemical Stability Metals: Will lose ve- to reach stability. Form cations (+ charged atoms) Non-metals: Will gain ve- to reach stability. Form anions (- charged atoms) Chemical Stability Determine what type of ion each element below would form to reach maximum stability. a. b. c. d. e. Sodium Na1+ Oxygen O2Argon Ar Phosphorus P3Chromium Cr2+ Bell Ringer: Chemical Stability 1. Write down what comes to mind when you think about chemical stability for elements. 2. Label your periodic table with the following groups: Alkali metals (Group 1) Alkaline earth metals (Group 2) Halogens (Group 17) Noble gases (Group 18) Transitional metals (Group 3-12) Periodic Table and Groups Ions and Chemical Stability Lab In pairs, look at 16 different elements and answer the following questions: a. Metal or non-metal b. Neutral, anion, or cation. c. Symbol and specific charge if needed. *neutral if element is naturally stable (noble gas) *anion: non-metal not naturally stable *cation: metals Size of an Ion Use the diagram below to determine what happens to the size of an atom when it becomes an ion. Size of a Cation A cation is smaller than its parent atom. Why? Because metals will lose an energy level in the process of becoming a cation. Size of a Cation Size of an Anion Size of an Anion A anion is larger than its parent isotope. Why? Repulsion force increases as more electrons are added to the outer most energy level. Swells the energy leve Size of an Anion Size of Ions a. Circle the atom that is larger in size. Ca or Ca2+ b. S or S2- 1. Circle the atom that is smaller in size. a. Al or Al3+ 2. b. N or N 3- Bell Ringer: Chemical Stability 1. a. Most stable group on periodic table? Explain. b. Most reactive metallic group? Explain. c. Most reactive non-metallic group? Explain. 2. Predict what type of ion each element below would form to reach maximum stability. a. Cesium b. Selenium c. Helium 3. Identify which atom is larger in each example below. a. Al or Al3+ b. Br or Br 1- Periodic Trends Periodic Properties and Trends Atomic Radius: -Size of an atom. - Distance from nucleus to highest energy level for that atom. (picometers, pm). - Ionization Energy: Energy required to remove an electron from an atom. Energy required to form a cation. Periodic Trends: Atomic Radius Atomic Number vs. Atomic Radius 200 atomic raidus (pm) 180 160 140 120 100 80 60 40 20 0 1 2 3 4 5 6 7 8 9 10 11 12 atomic number 13 14 15 16 17 18 Periodic Trends: Atomic Radius Across a Period Atomic Number vs. Atomic Radius 200 atomic raidus (pm) 180 160 140 120 100 80 Down a Group 60 40 20 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 atomic number Periodic Trends: Ionization Energy Atomic Number vs. Ionization Energy Ionization Energy (kJ/mol) 2500 2000 1500 1000 500 0 1 3 5 7 9 11 13 Atomic Number 15 17 Periodic Trends: Ionization Energy Atomic Number vs. Ionization Energy 2500 Ionization Energy (kJ/mol) Across a Period: 2000 1500 1000 Down a Group: 500 0 1 3 5 7 9 11 Atomic Number 13 15 17 Exit Slip 1 Use your graph on atomic radius and ionization energy answer these questions: a. Rank the following elements from largest to smallest in size. Explain your results. Ar, Mg, S Al b. Rank the following elements from smallest to largest in ionization energy. Explain your results. Ne, Ar, He Periodic Table Representative Elements: tall groups . •Transitional Elements: short groups. • Hydrogen Lab