Goal 2.2.1 notes Chemical symbols - abbreviated way of writing an element Primarily originated from Latin names, names of scientists, and names of places An element name with a two letter abbreviation has the first capitalized and the second lower case Co is the symbol for the element cobalt CO is the symbol for the compound carbon monoxide The modern periodic table, elements are arranged by increasing atomic number (# of protons) Atomic number increases from left to right in each row and increases from top to bottom Atomic mass increases from left to right in each row and increases from top to bottom Atomic radius decreases from left to right in each row and increases from top to bottom

Periods-horizontal rows of elements (# 1-7), indicate the # of energy levels Two significant periods (both metals) are placed below the periodic table and named after their first elements: The Lanthanide Series contains “rare earth” elements #57-71 The Actinide Series (#89-103) contains elements, which contain unstable nuclei (meaning they are radioactive) Groups or families-vertical columns (#1-18) Elements in each group have similar chemical and physical properties (but not identical) Elements in each group have the same number of valence electrons (electrons in the outer energy level) Metals = all elements to the left of this stair-step line Nonmetals = elements to the right of this stair-step line Metalloids = elements next to the stair-step line (except Al – it’s a metal); they have properties of both metals and nonmetals

Alkali metals = Group 1, 1 valence electron, 1+ oxidation #, highly reactive metals Alkaline earth metals = Group 2, 2 valence electrons, 2+ oxidation # Transition elements = Groups 3 through 12. They are metals but have properties not found in other groups Halogens = Group 17, 7 valence electrons, 1- oxidation #, highly reactive nonmetals Noble gases = Group 18, are non-metals but are extremely stable and unreactive

Classes of elements Metals: Hard, shiny solids (except Mercury –Hg) Metal are losers! They tend to lose electrons when bonding Good conductors of heat and electricity Malleable-they can be hammered or rolled into sheets Ductile-they can be drawn into wires All the elements in Groups 1 through 12 are metals except hydrogen Nonmetals: Most nonmetals are gases at room temperature Nonmetals tend to gain or share electrons when bonding They are dull, brittle and powdery Poor conductors of heat and electricity Hydrogen is considered a non-metal Metalloids: elements with properties that fall between metals and nonmetals For example, metals are good conductors and nonmetals are poor conductors. Metalloids ability to conduct electricity depends on temperature. Silicon is a good insulator at low temperatures but a good conductor at high temperatures. Along the stair-step line Boron, silicon, germanium, arsenic, antimony, tellurium, polonium, and astatine

Group # of valence Oxidation # electron Alkali metals 1 1+ Alkaline earth metals 2 2+ Transition metals Vary Vary Boron family 3 3+ Carbon family 4 4 Nitrogen family 5 3- Oxygen family 6 2- Halogens 7 1- Noble Gases 8 0 Electron dot diagram: represents the valence electrons of the element. www.youtube.com/watch?v=y6QZRBIO0-o Remember valence electrons are the electrons in the outer shell. They can be determined using the periodic table. Oxidation # is the charge of the ion. Remember that an ion is an atom w/ a charge.

Samples: 1. Which statement best describes one group of elements compared to another? a. Group 2 is less reactive than group 13 b Group 18 is more reactive than group 1 c. Group 14 is more reactive than group 15 d. Group 1 is more reactive than group 2

2. Which one of the element groups listed it the most stable? a. group 13 b. group 15 c. group 17 d. group 18 3. Francium is an element found in group 1 and period 7. How many valence electrons does an atom of francium contain? a. 1 b. 6 c. 7 d. 8

4. Radium is an element found in group 2 and period 7. How many energy levels does an atom of radium contain? a. 1 b. 6 c. 7 d. 8

5. Noble Gases are nonmetallic elements that do not readily react w/ other elements. What accounts for this non-reactivity? a. Noble Gases have an even # of protons and electrons. b. Noble Gases have an even # of protons and neutrons. c. Nobel Gases have 8 valence electrons. d. Noble Gases have an atomic number of 8.

6. Iodine is a halogen found in group 17 and period 6. How many valence electrons does iodine have? a. 6 b. 7 c. 11 d. 17

7. Where in the periodic table are the most reactive non- metals found? a. nearer the upper left b. nearer the lower left c. nearer the upper right d. nearer the lower left

8. Which group or family of elements in the periodic table has only one valence electron? a. the alkaline earth metals b. the alkali metals c. the halogens d. the noble gases 9. Which two elements have similar chemical properties according to the periodic table? a. He and Ar b. O and N c. Li and Ca d. B and Li

10. Which group contains the most reactive metals? a. the alkaline earth metals b. the alkali metals c. the halogens d. the noble gases

11. Which group contains the most reactive nonmetals? a. the alkaline earth metals b. the alkali metals c. the halogens d. the noble gases

12. Which group contains unreactive elements? a. the alkaline earth metals b. the alkali metals c. the halogens d. the noble gases

13. All of the elements in the halogen family a. need to give up one electron to become stable b. need to gain one electron to become stable c. do not react at all with other elements d. do not need to gain one electron to become stable

14. Which of the following is a correct statement about a periodic trend? a. In general, the atomic radius of elements decreases going down the Periodic Table. b. In general, an electron is more tightly bound to its atom going from left to right across the Periodic Table. c. The reactivity of metals decreases going down the Periodic Table. d. In general, the atomic radius of elements increases going from left to right on the Periodic Table.

15. Where are the halogens located on the Periodic Table? a. Group 1 b. Row 1 c. Group 2 d. Group 17 e. Group 18 f. groups 3-12

16. How would a bromine atom most likely gain a full outer shell? A. lose 7 electrons b. gain 7 electrons c. lose 1 electron d. gain 1 electron

17. Which atom is correctly paired w/ its oxidation #? a. Na –7 b. Cl +7 c. Ar –8 d. Ca +2

18. Which electrons are involved in the bonding process? A. electrons in the next to the last shell b. electrons closest to the nucleus c. electrons in the inner shells d. electrons in the outer shell