1. Describe a group or family of elements? (answers vary) the Noble gases have a completed set of valence electrons at the end of each period and therefore do not react with any other elements.
  2. Describe the chemical reactivity of the following families: halogens, alkali metals, noble gases. Halogens and alkali metals are highly reactive because they are one (lost/gained) valence electron away from stability. Noble gases already have a completed set of VE so have no need to react.
  3. What is another name for a row on the Periodic Table? Period
  4. How many rows are there on the Periodic Table? 7
  5. Pick two families of the Periodic Table and compare their chemical/physical properties. (answers vary)
  6. Why is the Periodic Table “periodic”? Chemical and physical properties repeat in “periods” or rows when elements are arranged in order by atomic number because valence electron energy levels are completed from left to right such that the first element in each row has the same number of valence electrons and similar chemical properties and the second element in each row has 2 valence electrons and so on until reaching completion in the far right column, the unreactive Noble gases, where the energy level of electrons is completed.
  7. What is an isotope? Give 2 examples. Isotopes are “heavy” versions of the same atoms with extra neutrons : such as C12 versus C14 are carbon atoms with two extra neutrons that have an atomic mass of 14 instead of 12.
  8. How many neutrons are there in an atom of carbon-14 answer: 8
  9. How many neutrons are there in an atom of carbon-13 answer: 7
  10. What would happen if you added 4 neutrons to an atom of carbon-13? Carbon-17 would be unstable.
  11. What is an ion? Give 2 examples. Ions are atoms with + or – net electrical charges. When sodium and chlorine react Na loses 1 electrons and becomes Na1+ while Cl gains 1 electron to become Cl1-

33. How many electrons are there in an atom of Na+1: answer: 10

34. How many electrons in an atom of Cl-1? Answer: 18

35. What would happen if you added 2 protons to an atom of oxygen? It would become a Neon isotope.

36. What would happen to the mass and identity of a calcium atom if you added 1 proton and 5 neutrons? It would be an atom of scandium with a mass of 46 amu (atomic mass units)

37. What is an ion? An ion is a + or – charged atom.

38. Why are the elements on the Periodic Table considered electrically neutral? Have the same # e- & p+

39. If a calcium atom started neutral, but then lost 2 valence electrons-- what is its new (net) electrical charge? Ca2+