Introduction to the Periodic Table Init: 9/18/2008 by Daniel R. Barnes . . . explain the meaning and origin of information found on the periodic table. “SWBAT = “Students will be able to” Atomic number = number of protons The atomic number defines the element. If an atom has 11 protons, it’s a sodium atom, guaranteed. If an atom is a sodium atom, it has 11 protons, guaranteed. If it hasn’t got 11 protons, it’s not sodium. It’s some other element = Natrium First letter upper case, all others lower case The symbol and the name don’t always match. When this happens, it’s probably because the symbol is taken from the Latin name for the element. The Roman Empire “Ferrum” is Latin for “iron”. 26 Fe 55.85 “Argentum” is Latin for “silver”. “Aurum” is Latin for “gold”. 47 Multi ex scientia verba latina (?)* Ag 107.87 79 Au 196.97 “Stannum” is Latin for “tin”. 50 Sn 118.71 * I used the translate function on iGoogle for this. I don’t think it’s trustworthy for English Latin, to tell you the truth. You get to use the CST Refence Sheet on all the tests in this class. Therefore, you don’t have to memorize all the names and symbols of every element on the periodic table. It helps, though. Although it would surprise Dalton to find this out, not all the atoms of an element have the same mass. An atom of an element is guaranteed to have a certain number of protons (the atomic number of the element). However, an atom does not have to have a specific number of neutrons to be in that element. 6 C carbon 12.01 Therefore, each element occurs as several different isotopes, each of which has a specific mass number. Most carbon atoms are carbon-12 atoms, but there are some carbon-13 atoms, also. That drives the average mass up a bit. Q1: What is the atomic number of silicon and what does this mean? A: The atomic number of silicon is 14, which means all silicon atoms have 14 protons, and any atom with 14 protons is a silicon atom. Q2: What is the difference between Co and CO? A: “Co” is the symbol for cobalt, a metallic element. “CO” is the formula for the compound carbon monoxide, a colorless, odorless, and highly toxic gas. Q3: Why is the symbol for silver “Ag” instead of “S” or “Si”? A: “S” was already taken by sulfur, and “Si” was already taken by silicon. Therefore, scientists based the symbol for silver on silver’s Latin name, “argentum”. . . . describe the location of any element on the periodic table. “SWBAT = “Students will be able to” Period one Period five Period seven Period seven eighteen Column Group eighteen Group six six Column one Column Group one What element is at Row 4, Column 12? What element is at Period 6, Column 3? What element is at Row 2, Group 17? What is the location of manganese? Period 4, Group 7 What is the location of platinum? Period 6, Group 10 What is the location of argon? Period 3, Group 18 . . . relate the position of an element on the periodic table to its atomic number and atomic mass. “SWBAT = “Students will be able to” Look at what the average atomic masses do as atomic number increases Average Atomic Mass/amu Average Atomic Mass vs. Atomic Number Atomic Number http://web.mit.edu/course/3/3.091/www3/pt/pert3.html 52 53 Te I 127.60 126.90 27 28 Co Ni 58.93 58.69 18 19 Ar K 39.95 39.10 There are more reversals around here, somewhere, but don’t worry about them right now. Where are all the light elements? The darkened darker it is, the heavier it is. in proportion to the I’ve each square here atomic are number of heavy the element in the square Where all the elements? What happens to average atomic mass as you go to the right? It gets larger. What happens to average atomic mass as you go down a column? It gets larger. Q4: What is the relationship between position on the periodic table and atomic mass/atomic number? A: Atomic numbers and atomic masses get larger as you go down or to the right. User name = hwbrainpop Ask Mr. Barnes for password. Can’t give it here. I post this ppt on the www. (9/16/2014) View the “Periodic Table of the Elements” cartoon once you’ve logged in. The student account is only good from the hours of 8AM – 4PM. The End 18 19 Ar K 39.95 39.10 Scrap Junkyard Not part of lecture! 27 28 Co Ni 58.93 58.69 52 53 Te I 127.60 126.90