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Periodic Table of Elements PA Standards Assess and apply recurring patterns in natural and technological systems. (3.1.12 C.1) Compare and contrast structure and function relationships as they relate to patterns (3.1.12 C.2) Know and use on-going scientific processes to continually improve and better understand how things work (3.2.12 A.1) Apply knowledge of complex physical models to interpret data and apply mathematical models. (3.1.12 B.2) Examine and describe recurring patterns that form the basis of . . . chemical periodicity . . . . (3.1.10 C.1) Compare and contrast scientific theories and beliefs. (3.2.10 A.1) Explain how the forces that bind solids, liquids and gases affect their properties. (3.4.12 A.4) Explain the formation of compounds and their resulting properties using bonding theories. (ionic and covalent). (3.4.10 A.5) Explain the repeating pattern of chemical properties by using the atomic structure within the periodic table. (3.4.10 A.2) 5.1 Early History of the Periodic Table When you go to the library to find a book, how do you locate it? If it is a fiction book, you look by author since the fiction materials are filed by the author’s last name. If you are looking for a non-fiction publication, you look in a catalog (most likely on a computer these days). The book you are looking for will have a number by the title. This number refers to the Dewey Decimal system, developed by Melvil Dewey in 1876 and used in over 200,000 libraries throughout the world. Another system in wide use is the Library of Congress approach, developed in the late 1800s-early 1900s to organize the materials in the federal Library of Congress. This method is one of the most widely used ways to organize libraries in the world. Both approaches organize information so that people can easily find what they are looking for. Chemistry information also needs to be organized so we can see patterns of properties in elements. 5.2 Mendeleev Mendeleev ______________ of the Periodic Table When a person is confronted with a large number of items, it is only natural to look for similarities that can be used to develop a classification scheme. A person who collects baseball cards may group his cards according to team or position. Biologists classify all living organisms in a fivekingdom classification system, based on similar characteristics. In 1869 Dmitri Mendeleev, a Russian Chemist, published the first periodic table. It had eight columns and it contained blank spaces for elements that Mendeleev predicted must exist, although they had not yet been discovered. 5.3 Periodic Law A study of the periodic tables shows certain regularities in the properties of the elements. This similarity occurs because the members of a group have the same number of valence electrons. Valence electrons are how many electrons are in the outermost shell or period. Periodicity or PERIODIC LAW _________________________________________________________________ For Example, Alkali metals all have similar properties; react with water and have 1 valence electron. 5.4 Periods and Groups Groups or Families Unlike Mendeleev's table, the modern Periodic Table is arranged according to atomic number. Remember that it is the atomic number, or nuclear charge, that determines the identity of the element. The horizontal rows of elements on the periodic table are called periods. The vertical columns are called groups or families. By looking at the column that an element is found in, you can predict the valence shell configuration with a good deal of accuracy. Solids Liquids and Gases What are the only 2 liquids on the periodic table?______________________ 5.5 Metals 5.6 Nonmetals 5.7 Metalloids The Line Metals 5.8 Blocks Nonmetals Metalloids 5.9 Hydrogen and Alkali Metals List 3 facts of the Alkali Metal Family 1. 2. 3. 5.10 Alkaline Earth Metals List 3 facts of the Alkali Metal Family 1. 2. 3. 5.11 Noble Gases List 3 facts of the Noble Gas Family (Inert) 1. 2. 3. 5.12 Halogens List 3 facts of the Halogen Family 1. 2. 3. 5.13 Transition Metals List 3 facts of the Transition Metal Family 1. 2. 3. 5.14 Daltons Atomic Theory Dalton’s Atomic Theory (1804) From his experiments and observations, as well as the work from peers of his time, Dalton proposed a new theory of the atom . This later became known as Dalton’s atomic theory . The general tenets of this theory were as follows: All matter is composed of extremely small particles called atoms . Atoms of a given element are identical in size, mass, and other properties. Atoms of different elements differ in size, mass, and other properties. Atoms cannot be subdivided, created, or destroyed. Atoms of different elements can combine in simple whole number ratios to form chemical compounds . In chemical reactions , atoms are combined, separated, or rearranged 5.15 Thomson’s Atomic Theory Tape Activity – Thomson Plum Pudding Part 1 – Preparing the tapes - examining their behavior 1. Take a 15 cm piece of transparent tape and make a handle on the end by folding under the first cm of tape, sticky side to sticky side. Place this tape on the lab table. This is the base tape. 2. Take a second 15 cm piece of transparent tape, make a handle as before, and place this tape on top of the base tape. Label this tape “B” for bottom. 3. Attach a third similarly prepared strip of tape onto the bottom tape. Label this tape “T” for top. 4. Peel one set of T and B tapes from its base tape, keeping the T and B tapes together. Run your finger down the non-sticky side, then quickly peel them apart. 5. Hang each strip next to the hanging paper and foil and variety of other objects. Data Table Charge Hair Balloon Top Tape Bottom Tape Wall Shirt Al Can Styrofoam Plastic bag Aluminum Foil Paper Plastic hair comb 1st Model 2nd Model ___________ __ _____________ Thomson did experiments on the beams of particles in his tube. They were attracted to a positive charge, so Thomson correctly concluded that they must be negatively charged themselves. He called the tiny, negatively charged particles electrons. But where had these tiny particles come from? Since they were so small, Thomson suggested that they could only have come from inside atoms. So Dalton's idea of the indestructible atom had to be revised. Thomson's model of atomic structure is often called the plum pudding model. He postulated that the negatively charged electrons, he had recently discovered, were scattered throughout a cloud of positive charge, like the plums in plum pudding. The plum pudding model could not however predict why atoms attract or repel each other. 5.16 Rutherford’s Atomic Theory Gold Foil Activity - Rutherford Activity 1 Choose an activity 1. 2. 3. 4. Use rubber cement to attach the four plastic cups to each corner of the foam board. Fasten the central object (representing the atom’s nucleus) to the center of the board. Flip the model over so that the four plastic cups are supporting the card board. Have students assemble in groups of four or five. Alternate rolling marbles under the foam board while the other students observe and record the different directions and angles that the marbles are deflected out. Activity 2 5. Use tape to form a circle with an opening. 6. Place half a Styrofoam ball in center. 7. Alternate rolling marbles in circle, while the other students observe and record the different directions and angles that the marbles are deflected out. tape o marble Activity 3 8. Use a circle dome to represent the nucleus. 9. Use a water gun to try and hit the gold foil. 10. Remove the dome and observe how wet it is. If it is dry then the water was deflected. Marble/gun Pass Through Deflected Back Deflected at an angle 1 2 3 4 5 6 7 Questions 1. What does the center of the model represent? 2. What do the marbles represent? 3. When the particles deflect, what does that represent? 4. How does this change our current model? 5. Why do some of the marbles pass straight through, and others are deflected back? Explain with respects to Rutherford’s experiment. 6. How does this experiment relate to Ernest Rutherford’s discovery of the nucleus of an atom? 2nd Model 1st Model ____________ ____________ 3rd Model _____________ In 1911, Ernest Rutherford performed an experiment to test the plum pudding model. He fired energetic positive [He2+] particles at a foil, and measured the deflection of the particles as they came out the other side. From this he could deduce information about the structure of the foil. To understand how this works, imagine shooting a rifle at a mound of loose snow: one expects some bullets to emerge from the opposite side with a slight deflection and a bit of energy loss depending on how regularly the pile is packed. If the mound were made of loose, powdery snow, the bullets would be deflected very little; if the bullets were deflected wildly, we might guess that there was a brick of hard material inside. Rutherford expected all of the particles to be deflected just a bit as they passed through the plum pudding. He found that most of the positive he shot at the foil were not deflected at all. They passed through the foil and emerged undisturbed. Occasionally, however, particles were scattered at huge angles. Rutherford’s result lead him to believe that most of the foil was made of empty space, but had extremely small, dense lumps of matter inside. With this experiment, Rutherford discovered the nucleus. 5.16 Bohr’s Atomic Theory Flame Tests Activity - Bohr When elements are heated to high temperatures, they may be placed in an excited state. In an excited state, the electrons move to high energy levels. As the electrons move back down to the ground state, they emit light in a specific color. The longer the distance they move, the higher energy wave lengths get emitted. The shorter distance the electron moves, the lower the energy. E= height x frequency; more height = more distance = more energy Three of these elements give characteristic colors when heated in a flame: Family I Alkali Metals Color Wavelength Lithium Sodium Potassium Predict Cesium Family II Alkaline Metals Color Wavelength Magnesium Calcium Barium Predict Radium 1 st Model 2nd Model 3rd Model 4th Model ______ ______ _____ _____ ______ ______ Evolution of Atomic Theory evolve (ē välv′, -vôlv′; i-) to develop by gradual changes; to produce or change by evolution; that how the model of the atom originated and how our understanding of the atom has changed over the years Evolution of the Atom Bensalem High School Chemistry Abstract __________________________________________________________________________________ __________________________________________________________________________________ __________________________________________________________________________________ __________________________________________________________________________________ __________________________________________________________________________________ __________________________________________________________________________________ __________________________________________________________________________________ __________________________________________________________________________________ __________________________________________________________________________________ __________________________________________________________________________________ __________________________________________________________________________________ __________________________________________________________________________________ __________________________________________________________________________________ __________________________________________________________________________________ __________________________________________________________________________________ __________________________________________________________________________________ __________________________________________________________________________________ __________________________________________________________________________________ __________________________________________________________________________________ __________________________________________________________________________________ __________________________________________________________________________________ __________________________________________________________________________________ __________________________________________________________________________________ ______________________________________________ Dalton's Atomic Theory created in 1803 All elements are composed of indivisible particles Atoms of the same element are exactly alike Atoms of different elements are not alike Compounds are formed by joining atoms of two or more Thomson's Atomic Model Plum pudding in 1897 Said that the atom consists of positively charged protons and negatively charged proved that an atom could be divided said the atom is neutral Rutherford's Atomic Model in 1903 showed that the Atom has a nucleus inside the nucleus are protons and neutrons the nucleus's size can be compared to a bee in a stadium outside the nucleus are the electrons in the electric cloud electrons discovered this by shooting charged particles through a gold sheet and counting the number of particles that went through Bohr's Atomic Model created in 1913 Electrons orbit around the nucleus in a orbit proposed that electrons move in energy levels 5.18 Proton Electrons and Neutrons PEN Protons Protons are positively charged subatomic particles that found, along with neutrons, in the nucleus of the atom. Protons, along with neutrons, make up most of the mass of the atom. Although the positive charge of the proton is equal to the negative charge on the electron, one proton has as much mass as around 1840 electrons. The elements on the periodic table are arranged in order of increasing number of protons. are Atomic Number The number of protons in the nucleus of an atom is called its atomic number. The atomic number, which is given the symbol Z, is what determines the identity of an element. All atoms of the same element have the same number of protons and the same atomic number. Atoms of different elements, by definition, will have a different number of protons and therefore, different atomic numbers. Elements with the atomic numbers from 1 to 112 have been identified so far. One of the numbers found in each elemental box on the periodic table will be the atomic number. Unlike the mass number, the atomic number is always a whole number. Neutrons The neutron is a neutral particle that is found in the nucleus of most atoms. Although the neutron has no charge, it does contribute to the mass of the atom. Each neutron has a mass of about 1.67495 x 10-24 grams, or 1.0087 u. The most common type of hydrogen, called protium, has no neutrons. 5.19 Atomic Mass Atomic Mass The mass of an atom is found in the nucleus. The mass of a proton or a neutron is approximately 1 u (atomic mass unit). It would take around 1840 electrons to equal the mass of one proton. For this reason, the masses of the electrons are not considered when calculating the mass number of an atom. The mass number, which is given the symbol A in elemental notation, consists of the total number of protons and neutrons in the nucleus of the atom. Atoms are made up of 3 types of particles electrons , Protons These particles have different properties. Electrons are tiny, very light particles that have a negative electrical charge (-). Protons are much larger and heavier than electrons and have the opposite charge, protons have a positive charge. Neutrons are large and heavy like protons, however neutrons have no electrical charge. neutrons . PEN Homework 4 2 He 56 26 Fe 27 13 element: _________________ element: _________________ # protons: _______________ atomic #: ________________ # neutrons: ______________ mass #: __________________ 40 20 Ca 20 10 element: _________________ # protons: ________________ # electrons: _______________ Ne O 16 element: _________________ element: _________________ # protons: _______________ atomic #: ________________ average # neutrons: ________ Al # electrons:_______________ element: _________________ # protons: ________________ # electrons: _______________ 59 24 12 Mg element: _________________ 27 Co Zn 30 element: _________________ atomic #: _______________ atomic #: ________________ mass #: ________________ # electrons:_______________ 19 9 F element: _________________ 1 1 H element: _________________ atomic #: _______________ atomic #: ________________ mass #: ________________ # electrons:_______________ element: ________________ # protons: ________________ # electrons: _______________ 52 24 Cr element: ________________ # protons: ________________ # electrons: _______________ 5.20 Millikan Oil Drop Experiment Millikan carried out a series of experiments between 1908 and 1917 that allowed him to determine the charge of a single electron, famously know as the oil drop experiment. He sprayed tiny drops of oil into a chamber. In his first experiment, he simply measured how fast the drops fell under the force of gravity. He could then calculate the mass of the individual drops. Then he sprayed oil drops and applied an electrical charge to them by shining X-rays up through the bottom of the apparatus. The X-rays ionized the air, causing electrons to attach to the oil drops. The oil drops picked up static charge and were suspended between two charged plates. Millikan was able to observe the motion of the oil drops with a microscope and found that the drops lined up in a specific way between the plates, based on the number of electric charges they had acquired. 5.21 Trends in the Periodic Table Reactivity Trends Activity in the Periodic Table Element Chemical Symbol React (Chemical Properties) Observations (Physical Properties) Family State of Matter Non-metal Metal or Semi-Metal Phase of Matter Solid Liquid or Gas Lithium Sodium Potassium Magnesium Calcium Antimony Carbon Sulfur Fluorine Bromine Helium Xenon Silicon Copper Chromium Iron Tin Periodic Table Review Questions 1. Arrange the Group I metals in order of reactivity from most reactive to least reactive. ______________________________________________________________________ 2. Is the same trend seen in the Alkaline Earth Metals, which was more reactive Ca or Sr? ______________________________________________________________________ 3. Compare the reactivity of Na, K & Ca, in water. Which group is more reactive ( I or II)? ______________________________________________________________________ 4. What is the trend in reactivity seen within the family 7 of the periodic table? ______________________________________________________________________ 5. For metals what is the trend in reactivity seen within the same family of the periodic table? ______________________________________________________________________ 6. Which would be the most reactive metal in the periodic table? ______ nonmetal?_______ 7. Which metal is a liquid at Room Temperature? ____________nonmetal?_____________ 8. What is the trend in reactivity seen within the family 8 of the periodic table? __________ 9. Why are the noble gases so “noble”? ________________________________________ 10.Complete the following by labeling the periodic table on the next page. a. Label Group A 1 – 8 and Group B b. Label Solids, liquids, and gases c. Label s, p, d, and f sections d. Label Non metals, metals, semi-metals LINE e. Label alkali, alkaline, transition, halogens, and noble families If Potassium reacts violently when exposed to water, why don’t we blow up when we eat a banana? What atomic theory would support bioluminescence? Would element could the angler fish in NEMO’s be? What wavelength would it emit? Draw the Bohr model of the element