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M7 THE ATOM Foundational Research Package II A CLOSER LOOK AT THE STRUCTURE OF MATTER December 2007 - Team E Science Name: ____________________________________ Section: ______________________________ TABLE OF CONTENTS Introduction, Objectives and Study Guide………..1 Research and Practice Properties of Atoms…………………………..2-6 The Bohr Model Revisited..…………………...7-8 The Periodic Table……………………………9-14 We have just concluded our intro to the heart of the matter. From this experience, we were able to discover: 1) 2) 3) 4) the the the the classes of matter. history of the atom. structure of the atom. forces of the atom. We are now going to get deeper into the heart of the matter with a look at the following questions and concepts. PROBLEM 1: How do we distinguish between the atoms of different elements? THE FIVE PROPERTIES OF ATOMS Chemical Symbol Chemical Name Atomic Mass Atomic Number Mass Number (and Isotopes) PROBLEM 2: How do we illustrate the structure of the atom? THE BOHR MODEL Determination of number of subparticles Placement of subparticles Predicting bonding PROBLEM 3: How do we organize the elements for studying purposes? THE PERIODIC TABLE Periods/Rows vs. Columns Meaning of column #’s Families: Non-metals, Metals, Metalliods, Inert/Noble Gases Now that you know what we’ve got to learn, let’s get a-learning…NOW! FYI – your quiz on these questions is planned for NEXT THURSDAY…December 20th! You will be asked to answer questions on ONE element. This packet, as well as your review packet (M-8), will be the materials you need to study for this quiz. PROBLEM #1 How do we distinguish between the atoms of different elements? A closer look at the properties (i.e. characteristics) of the atom In this section of our closer look at the atom, we will take a look at how we distinguish between the atoms of different elements. First, let’s define what a “property” is and why it is important in studying atoms. What is a “property” of an atom and why do we need to refer to these “properties” when we are talking about atoms? _______________________________________________________________________________________ _______________________________________________________________________________________ There are FIVE properties of atoms that you need to know about and understand. They are… Property Definition The first two properties, the chemical ________ and _________, are Chemical the ways that we label or “call” or “name” atoms. The symbol comes Name and from the first letter or letters in the chemical’s _____________ or Symbol ______________ name. The third property, __________ ___________, is equal to the number of protons OR electrons. It is the property that gives an atom Atomic Number the chemical characteristics that make it different from other atoms. Why? Because if you change the number of ______ and _______ in an atom, you are changing its IDENTITY and all that makes it what it is (i.e. its _______________) and what it can do with other atoms (i.e. __________). Location in an entry on Periodic Chart The fourth property, the _____________ _______________, tells us how much “matter” or _______________ or a.m.u.’s there is/are in the ___________atom of an element (i.e. the number of ____ and ____ ). Atomic Mass Why is there an average mass? The mass of an element can be different from atom to atom of that element. This is because ________can never change for a given atom, but ________ can because they have a _________ charge and therefore will not change the atom’s identity but will change its __________. The fifth property, the _______ ____________, is the _________ Mass Number mass of an __________ atom…not the __________ from the periodic chart. Therefore, it is the __________ amount of _______ and ________ in an ________ atom. This _________ sample of an element is called an __________. AN ENTRY FROM THE PERIODIC TABLE… Identify the properties in this entry from the periodic table. _________________ _______________________ 1 ____________________ H ________________________ _________________________________ Hydrogen 1 Now assume you are given an isotope for Hydrogen. We identify an isotope by writing its chemical name followed by a dash and then its mass number. An example isotope of Hydrogen is Hydrogen-2. How would this isotope of Hydrogen be different from the average atom that is listed on the Periodic Table? ________ _________________________________________________________________ __ H Hydrogen __ ________ _________________________________________________________________ _________________________________________________________________ PART I. PROPERTIES OF ATOMS PRACTICE PROBLEMS Cu-60 Copper (Cu) He-3 Helium (He) B-11 Boron (B) Mg-28 Magnesium (Mg) Pb-207 Lead (Pb) Chemical Name Isotope (Actual Sample) Atomic Mass Atomic Number Mass Number Electrons Protons Average Neutrons Isotope Neutrons Difference? Below is a list of the properties of isotopes of five different elements. Use the information given to you, your notes on properties of atoms, and the periodic chart in your green folder to fill in the missing information. PART II. USES OF ISOTOPES So…what’s the big deal about isotopes? Why is it so important that there are atoms of the same element that have different amount of neutrons? To figure this out… Pick an isotope from the attached list. Read the information about your selected isotope. Grab your periodic table. Answer the following questions. 1) Pick one of the isotopes and write its name here:_________________________________ 2) How does the isotope you selected differ from the average atom that is shown on the periodic chart? Fill in the information below and then explain the difference(s) (if there is/are one/any!) in the space provided. THE PERIODIC CHART INFO: ISOTOPE INFO: Atomic # ____ ____ Chem. Sym. ____ Atomic Mass ____ Mass Number __________________________________________________________________________________________ __________________________________________________________________________________________ 3) Why is the isotope you selected important? In other words, what special property does it have and/or what do we use it for? __________________________________________________________________________________________ __________________________________________________________________________________________ __________________________________________________________________________________________ __________________________________________________________________________________________ EXAMPLES OF ISOTOPES PROBLEM #2 How do we illustrate the structure of the atom? A FINAL and CLOSER look at the Bohr Model The Bohr Model is something that should be relatively familiar to you…but NOW is the time to really get a grip on it! WARNING! This might just be a little “Bohring” since you already know a bit about it! SO, hot-shot scientists, let’s see what you know by trying to fill out the important info about the Bohr Model in the space below… THE PURPOSE OF THE BOHR MODEL The purpose of the Bohr model is to: 1) _______________________________________________________________________________________ 2) _______________________________________________________________________________________ THE PROCEDURE FOR MAKING A BOHR MODEL – this works for the first _____ elements ONLY! 1) Get a ______________ _____________!!! (or look at the info given about an isotope of an element) 2) Find the number of ______ in the atom by looking at the atomic ______________ for that atom. 3) Find the number of ______ in the atom by looking at the atomic ______________ again. This is same number as the number of ______ because atoms must be _______________. 4) Find the number of ______ by ______________ the atomic ________ FROM the atomic ___________ (or mass __________ if an isotope). 5) Draw the ______________ as a circle. Put the __________ __________ and the number of __________ and __________ in the circle. 6) Fill the __________ _____________ with the right number of ________ according to the pattern of ____ - ____ - ____ ! Do ________ fill a new _________ _________ until the level you are in is filled to its _________________ capacity! 7) Remember, for all subatomic particles it is necessary to put the __________ before the ___________ when listing the amount of the sub-particles in the atom! LET’S DO SOME “BOHRING” PRACTICE! 1) Do the Bohr Model for an isotope of Aluminum 13 Al 26 Is this isotope of Aluminum different from the average isotope of Aluminum? Explain your answer. ____________________________________________________________________________________ 2) Do the Bohr Model for an isotope of Sulfur 16 S 32 Is this isotope of Sulfur different from the average isotope of Sulfur? Explain your answer. ____________________________________________________________________________________ 3) Do the Bohr Model for an isotope of ????????????? 10 ? 20 What is the identity of the mystery isotope? Is this isotope different from an average isotope of that element? Explain your answer. ____________________________________________________________________________________ ____________________________________________________________________________________ Will this atom bond with other atoms? Why or why not? ____________________________________________________________________________________ PROBLEM #3 How do organize the elements for studying purposes? A look at the “periodic pattern” in the Periodic Table DO NOW: An isotope of oxygen has a MASS NUMBER of 9. Find oxygen on your periodic table (oxygen is located in the 3rd to last column). Use the information in your periodic table and the MASS NUMBER of this atom of oxygen to: 1) DRAW the Bohr model for this isotope of oxygen. 2) LIST the number of subatomic particles in this isotope of oxygen. 3) LIST how many more or less neutrons this isotope of oxygen has compared with the “average” isotope of an oxygen atom. Bohr Model: e- p+ Ø Difference in neutrons ONE MORE QUESTION: What could be the LOWEST possible MASS NUMBER for an isotope of oxygen? HIGHEST? Explain your answers. __________________________________________________________________________________________ __________________________________________________________________________________________ __________________________________________________________________________________________ __________________________________________________________________________________________ __________________________________________________________________________________________ INTRODUCTION TO THE PERIODIC TABLE… The Periodic Table A scientific problem. A periodic pattern to be discovered. Two detectives. One answer found and reformulated. Now, for the “rest” of the story… The Russian scientist Dmitri Medeleev was the first chemist responsible for “creating” the periodic chart of elements. Scientists during Dmitri’s time were trying to figure out an easy way in which they could organize the elements of matter so that it would be easy for them to communicate about their properties (i.e. scientists, even back then, were lazy and they didn’t want to have to memorize all the elements and their properties). Dmitri was, as are all scientists, a problem solver. His problem was to organize the elements into a predictable, easy to understand way…he want to predictably order or .“periodically arrange” the elements in a way that relate the elements properties to their placement in a table. To solve this problem – to organize the elements into a table that had a periodic or predictable pattern of element properties – Dmitri first made cards of all the known elements. On each card he wrote the element’s name and all of its properties (e.g. atomic mass, density, color, melting point, and ability to BOND with other elements). The ability to bond with other elements was expressed as VALENCE NUMBER. This was a number that reflected the number of electrons that the element would want to SHARE, LOSE, or GAIN when it combined with other elements. GET THAT? When atoms combine with one another, they either SHARE, LOSE, or GAIN electrons in their VALENCE SHELLS. The VALENCE NUMBER is the NUMBER of electrons that an atom will most likely LOSE, GAIN, or SHARE. This is different from the NUMBER of VALENCE ELECTRONS! The number of valence electrons is JUST how MANY electrons there are in the VALENCE SHELL…NOT how many the atom will most likely lose, gain, or share. As he was “playing cards,” Dmitri fell upon a pattern. By arranging them in order of atomic mass, he noticed that there was a pattern in the VALENCE NUMBER of the elements for EVERY SEVEN elements. The pattern was LOSE 1 e-, LOSE 2 e-, LOSE 3e-, GAIN OR LOSE 4e-, GAIN 3e-, GAIN 2e-, GAIN 1e-. Using this pattern as his guide and keeping to the order of increasing atomic mass, he then put the elements into columns instead of a long strand of elements: all the elements that would lose one electron were in column one, all the elements that would lose 2 electrons were in column two, etc. When he did this, he saw another pattern! The chart or table that he created was predictable and periodic according to atomic mass, valence number AND several other physical and chemical properties! The problem of creating a chart of the elements that reflected a predictable, periodic pattern of atomic properties had been solved…ALMOST! Some elements just didn’t seem to fit in to the pattern of increasing atomic mass and valence numbers. Science never stops, and the same holds true for the “creation” of the periodic table…50 years later a NEW atomic property – ATOMIC NUMBER (the number of protons and neutrons) – was discovered by another scientist: the Brit Henry Moseley. It was then that the pattern in the periodic table was truly founded…elements, instead of being ordered as a function of their atomic mass, were ordered as a function of their atomic number. The “periodic” pattern in the table of elements was based on ATOMIC NUMBER and VALENCE instead of ATOMIC MASS and VALENCE! …And, in the words of talk radio commentator Paul Harvey… “that’s the ‘rest’ of the story.” THE PROBLEM: HOW DO WE ORGANIZE THE ATOM FOR STUDYING PURPOSES? The answer… THE PERIODIC TABLE a.k.a. THE PERIODIC CHART a.k.a. THE TABLE OF ELEMENTS! NOTE: Thanks to those Russian and British dudes (Mendeleev and Moseley), the periodic table is arranged in a predictable…periodic …USEFUL way. It has a pattern to it…the properties of the elements are predictable according to their location…they repeat themselves periodically (hence the name “periodic” table). So...USE it to your ADVANTAGE! That’s why it’s there…that’s why it is arranged in the way that it is! YOU DON’T HAVE TO MEMORIZE THE ELEMENTS AND THEIR CHARACTERISTICS! By using the chart often, you will automatically become familiar with the elements and the characteristics! Here are some important periodic patterns in our most beauteous of all chemical charts. 1. The periodic table has __________________________. a) All the elements in EACH _______________ have the same # of ____________ electrons (the same # of electrons in the ___________ energy level). The main columns of the periodic table can be labeled so that the column # is the same # as the # of _____________ electrons in the atoms in that column…thus, _______________ can also be labeled with their VALENCE NUMBERS. Let’s label our periodic charts with these numbers now. b) Elements in the same ______________ DO share similar chemical and physical properties. c) Example: Beryllium has ___ electrons and ____ protons. It has _____ neutrons. 4 The Bohr model for Beryllium is: Be 9 It is located in column _____. It therefore has _____ electrons in its _________ shell. The Bohr model proves this! Its VALENCE NUMBER is _____. This means that it wants to ________ 2 electrons when it bonds with other atoms. 2. The periodic table has _____________ or _________. a) All the elements in the each _______________ have the same # of ___________ levels or shells. b) All elements in the same _______________ do ________ share similar chemical and physical properties. c) Example: 4 6 Beryllium and Carbon are both in period _____. The both have ____ energy Be C levels, but they do _______ have similar chemical or physical properties (e.g. they 9 12 are not in the same ___________)! 3. There are 4 major ________________ or categories in the periodic table. Each _____________ has a unique set of properties and characteristics. Because the periodic pattern in the periodic table is based upon the atomic ________________ and _______________ number of the elements, the families are each located in specific areas on the periodic table. The chart below outlines these families, their physical and chemical properties, the Noble or Inert Gases Metalloids Non-Metals Metals Family Location on Chart Chemical and Physical Properties types of bonds they make, and where they are located on the chart. A “CLOSER” LOOK AT THE STRUCTURE OF MATTER How do we illustrate the structure of the atom? GRAPHIC ORGANIZER PRACTICE Using your periodic table notes, fill out this template to make your own graphic organizer about the periodic table. Be sure to include: The column and period numbers. The meaning of the columns and periods (# of valence electrons/valence # vs. # of energy levels) The names of the families and their locations. The characteristics of the families. The “staircase.”