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CHAPTER 3 – STUDY GUIDE OBJECTIVES Learn the names and symbols for some elements Learn about the relative abundance of some elements Learn Dalton’s theory of atoms Understand the law of constant composition Learn how a formula describes a compounds composition Understand Rutherford’s experiment and its impact on atomic structure Describe important features of subatomic particles Learn about isotope, atomic number, and mass number Understand the use of the symbol Learn the various features of the periodic table Learn the properties of metals, nonmetals, and metalloids Describe the formation of ions from their parent atoms Predict which ion a given element forms by using the periodic table Describe how ions combine to form neutral compounds. SECTION 3.1 – THE ELEMENTS KEY TERMS: Element symbols At present, about _________ different elements are known. _______ of these occur naturally. The rest are _______________. The most abundant elements in the earth’s crust, oceans and atmosphere are ___________, ______________, and ______________. The most abundant elements in the human body are ______________, _______________, and ________________. _____________________ was a Irish scientist who insisted that science should be firmly grounded in _________________. When discussing elements, we can refer to them in the microscopic, macroscopic or generic sense. Tell the difference. Microscopic elements refer to Macroscopic elements refer to Generically, we discuss elements as Trace elements are present in ________________ amounts. Traces of ________________ are necessary for the proper functioning of the thyroid. _________________ is responsible for the production of red blood cells. Names and Symbols of the Most Common Elements Element Symbol Element Symbol Element H Aluminum Iron Sb Helium Iodine Ar C Pb Sodium Chlorine Sulfur Boron Potassium Nitrogen Ca Oxygen Mg Mercury P Li Si Bromine F Neon Symbol Ag Gold SECTION 3.2 KEY TERMS Law of Constant Composition Dalton’s atomic theory Atoms Compounds Chemical formula __________________________ explains important observations such as the law of constant composition. The main ideas of this theory are: 1. _________________ are made up of tiny particles called ________. 2. All atoms of a given element are ___________. 3. The atoms of a given element are ______________ from those of any other element. 4. Atoms of one element can combine with atoms of another element to form ____________. A given ______________ always has the same relative ____________ and _____________ of atoms. 5. Atoms are ________________ in chemical processes. This means atoms are not _____________ or _____________ in chemical reactions. A chemical reaction changes the way the atoms are ___________________________. The law of constant composition states that a given _____________ always contains ___________ in exactly the same proportion by _________. A ________________ is a substance made of two or more different ___________ joined together in a specific way. In a _____________________, the atoms are indicated by the _____________________________ and the number of each type of atom is indicated by a ________________, that appears to the _____________ of the symbol for the element. SECTION 3.3 – ATOMIC STRUCTURE KEY TERMS Electrons Nucleus Neutron Atomic Number Nuclear atom Proton Isotopes Mass number The Structure of the Atom Over the last 200 years the model of how we think of atoms has changed significantly four times. In 1897 an British physicist __________________________introduced the first model of the atom to include negatively charged particles called ______________________. note: (Later, a different Thompson named ___________________ Thompson reasoned that the atom might be a uniform positively charged "___________________" like form with electrons scattered around like the way raisins were distributed in plum pudding.) In 1909 ____________________________________, at physicist originally from New Zealand, showed the atom had a dense region with a positive charge. The region was called the ____________________. Rutherford's Experiment Ernest Rutherford studied, among many other things, __________________ (α) particles. Alpha particles are made of two_____________________ and two ______________________. They can be emitted by radio active material and fly through the air. In Rutherford's experiment he bombarded a thin foil of _______________ with these α particles. Alpha particles are invisible to the human eye but Rutherford surrounded gold foil with a screen that __________________ alpha particles. He found that most alpha particles passed through the gold foil but some were mysteriously deflected by something in the gold. Rutherford concluded there must be a ___________________ ____________________ in the center of the gold atoms that deflected the alpha particles. Rutherford's experiment showed that atoms had a __________. Later Rutherford also theorized that a nucleus is made of two particles: 1. ______________________ - a positive particle with an equal but opposite charge of an electron. Also significantly more massive than an electron. 2. ______________________ - a particle with no charge but similar in mass to a proton. Introduction to the Modern Atomic Structure SUBATOMIC PARTICLES symbol charge mass compared to the mass of one electron location neutrons protons electrons cloud 1 Element Symbol A ZX Atomic Number (Z) - the number of ____________________ identifies the element (all atoms of the same element have the same number of ______________) found on the _______________ ____________- (look in the back cover of your book) equal to the number of _____________________ in a neutral atom Mass Number (A) - the sum of the __________ and _________ What accounts for most of the mass of an atom? ______________________ What accounts for most of the volume of an atom? ____________________ Are all atoms of the same element identical? _________________________________. Isotopes - Atoms of the same element that have different numbers of __________________. They have identical atomic numbers but different ________________ numbers.