...Bond Types and Physical Properties PA State Standards: 3.4.10.A Explain concepts about the structure and properties of matter. 3.7.10.B Apply appropriate instruments and apparatus to examine a variety of objects and processes. 1.2.11.A Read and understand the central content of informational texts and documents in all academic areas. Introduction: The physical properties of compounds are determined by a variety of factors, and one of the most important is the type of bond holding the molecules together. There are many tests that can be performed to determine whether a molecule contains covalent or ionic bonds, and three of these tests will be utilized in this lab. The compounds will be tested for their solubility and conductivity in water, and their melting points will also be determined. Covalent compounds usually do not conduct electricity in water and have relatively low melting points. Ionic compounds are usually conductive in water and have very high melting points. Using data collected from these tests, bonds can be classified as covalent or ionic. Guiding Questions: Please answer the following questions before beginning the lab. 1. A compound has a melting point of 92 oC, does not dissolve in water, and does not conduct electricity in water. What type of compound is this? 2. A compound has a very high melting point, does dissolve in water, and conducts electricity in water. What type of compound is this? Equipment/Materials: Acetylsalicylic...
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...Earths surface and composes 55-70% of the human body. Water is an excellent solvent due to its chemical composition and physical attributes. According to USGS (http://water.usgs.gov/edu/qa-solvent.html ) Water molecules have a polar arrangement of the oxygen and hydrogen atoms—one side (hydrogen) has a positive electrical charge and the other side (oxygen) has a negative charge. A polar bond is a covalent bond between two atoms where the electrons forming the bond are unequally distributed. This causes the molecule to have a slight electrical dipole moment where one end is slightly positive and the other is slightly negative. "Like dissolves like" is an expression used by chemists to help them remember how solvents work. The expression refers to "polar" and "nonpolar" solvents and solutes. For example water is polar and Oil is non polar thus water will not dissolve oil. Therefore nonpolar molecules don't dissolve very well in water, including many organic compounds, such as fats and waxes. Water molecules can become attracted to several other types of molecules due to its polar bonds. Water can become so heavily attracted to a different...
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... NAME __Chelsea Dennis __ Dr. Shree Iyengar Homework #7 ------------------------------------------------- This homework covers the major concepts in Chapters 8 and 9, which are very closely related. You should consult the lab manual for relevant information on ‘geometries of molecules.’ There are Chapter notes available for this material under 'Modules' in Canvas. Learning Outcome for Chapters 8 and 9: When you complete reading the chapter and practicing the end-of-chapter exercises, you are expected the have the following skills as learning outcomes: * Use appropriate models of chemical bonding to explain the structure of molecules ------------------------------------------------- 1. Explain how the Octet Rule is used in the following situations; you should include relevant electron configurations to support your answer. a. ionic bond formation between Mg and P Mg would like to get rid of 2 electrons in the valence shell to obey the Octet rule and P would like to gain 3 electrons to obey the Octet rule. So P will take 2 of Mg electrons to become stable. b. covalent bond formation in NCl3 N would have to gain 3 electrons to obey the Octet rule and Cl would have to gain 1 electron. So N can pair with 3 Cl to become stable and Cl will be stable as well. 2. Write the abbreviated electron configuration for each of the following ions: a. Cr3+ b. Telluride...
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...3 element are being involved in the bonding - from just the one with sodium, to all seven of chlorine's outer electrons. The structures The trend in structure is from the metallic oxides containing giant structures of ions on the left of the period via a giant covalent oxide (silicon dioxide) in the middle to molecular oxides on the right. Melting and boiling points The giant structures (the metal oxides and silicon dioxide) will have high melting and boiling points because a lot of energy is needed to break the strong bonds (ionic or covalent) operating in three dimensions. The oxides of phosphorus, sulphur and chlorine consist of individual molecules - some small and simple; others polymeric. The attractive forces between these molecules will be van der Waals dispersion and dipole-dipole interactions. These vary in size depending on the size, shape and polarity of the various molecules - but will always be much weaker than the ionic or covalent bonds you need to break in a giant structure. These oxides tend to be gases, liquids or low melting point solids. Electrical conductivity None of these oxides has any free or mobile...
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...difference between ionic and covalent compounds and understand how their properties give rise to this categorization Introduction: It is amazing what early chemists accomplished even without an understanding of atomic make-up. Reading old chemistry textbooks shows how they justified some of their conclusions, which, with a few exceptions, were right on target. Some discussed the octet rule in terms of “valencies”, and they have it exactly right. What is interesting about this is that at that time they talked about this new sub-atomic particle that they were tentatively calling the “electron”. Another thing they had correct was the categorization of compounds into “covalent” and “ionic”. In class, you have discussed these compounds in terms of electrons, wherein ionic compounds transfer electrons and covalent compounds share electrons. How did the early chemists classify compounds, though, when they did not know what electrons were? They used properties, such as solubilities, melting points, and conduction. Solubility helps us to classify compounds as polar or non-polar, because, as a general rule, polar solutes dissolve in polar solvents (like water), while non-polar solutes dissolve in non-polar solvents (like oils). Conductivity means whether or not a compound will conduct electricity when it is dissolved in water. We call these “electrolytes”. An electrolyte will conduct electricity when dissolved in water, while a nonelectrolyte will not. Finally, ionic compounds tend to...
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...Topic 4 IB Chemistry What is a bond? • A force that holds atoms together and makes them function as a unit Atoms bond to achieve a noble gas electron configuration (8 electrons in the outer level - octet rule) • • H and He are notable exceptions - only need 2 electrons (duet rule) The valence electrons (electrons in the outermost energy level) are the ones involved • Ionic Bonds • The electrostatic attraction between oppositely charged ions (cation = +; anion = -) Results from the transfer of e- from a low electronegative atom (cation, metal) to a high electronegative atom (anion, non-metal) so both achieve complete outer shells (inert gas econfiguration) • • Ionic bonds occur if the difference in electronegativities is 1.8 or greater 2.8.1 • 2.8.7 Chlorine has a stronger attraction for the electrons than sodium; the valence electron moves from sodium to chlorine, resulting in the formation of oppositely charged ions (both atoms achieve a stable electron configuration of the closest noble gas); ions attract to one another 2.8 2.8.8 • The charge of an element is determined by its location on the periodic table • Some ions are formed from a group of atoms behaving as a single entity called polyatomic ions; the group has a single charge Ion NH4+ PO43NO3OHName ammonium phosphate nitrate hydroxide Ion CO32HCO3SO42Name carbonate hydrogen carbonate (bicarbonate) sulfate • Ionic substances must be neutral so the...
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...proportions to form totally new substances having very different properties to those of the elements of their make up. Compounds can only be separated by chemical reaction. To tell if it is a compound or an element, you have to know whether it is the element itself, or made up of 2 or more different elements that can be observed by seeing the formula. The two types of bonds are ionic bonds and covalent bonds. In an ionic bond, the atoms are bound together by the attraction between oppositely-charged ions. For example, sodium and chloride form an ionic bond, to make NaCl, or table salt. In a covalent bond, the atoms are bound by shared electrons. If the electron is shared equally between the atoms forming a covalent bond, then the bond is said to be no polar. Usually, an electron is more attracted to one atom than to another, forming a polar covalent bond. Explain why ionic compounds are formed when a metal from the left side of the periodic table reacts with a nonmetal from the right side. Give two examples of such compounds. The type of bond formed between 2 atoms is determined by the...
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...Electrons-carry a negative charge and encircles the nucleus. (http://education.jlab.org/atomtour/listofparticles.html) 2. Element A chemical element is a pure chemical substance consisting of one type of atom distinguished by its atomic number, which is the number of protons in its nucleus. http://en.wikipedia.org/wiki/Chemical_element 3. Compound A chemical compound is a pure chemical substance consisting of two or more differentchemical elements[1][2][3] that can be separated into simpler substances by chemical reactions.[4] Chemical compounds have a unique and defined chemical structure; they consist of a fixed ratio of atoms[3] that are held together in a defined spatial arrangement bychemical bonds. Chemical compounds can be molecular compounds held together bycovalent bonds http://en.wikipedia.org/wiki/Chemical_compound 4. Mass number The mass number (A), also called atomic mass number or nucleon number, is the total number of protons and neutrons (together known as nucleons) in an atomic nucleus. http://en.wikipedia.org/wiki/Mass_number 5. atomic number the atomic number (also known as the proton number) is the number of protons found in the nucleus of an atom and therefore identical to the charge number of the nucleus http://en.wikipedia.org/wiki/Atomic_number 6. octet rule The octet rule is a chemical rule of thumb that states that atoms of low (<20) atomic number tend to combine in such a way that they each have eight electrons in their valence shells...
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...Design Unit 1 Assignment 2 Alicia Gingrich 1. The three basic components of an atom are protons, neutrons, and electrons. While protons hold a positive charge, electrons hold a negative charge and neutrons hold no charge whatsoever. Protons and neutrons occupy the center of an atom called the nucleus while electrons maintain orbits around the nucleus. 2. The four types of bonding arrangements of atoms are; ionic, covalent, metallic, and Van der Waals bonding. An ionic bond links different types of atoms through the attraction between positive and negative charges, similar to the way magnets work. While these bonds are generally not conductive many are soluble and will conduct electricity once combined with water. Covalent bonds are made when atoms share their ‘valence’ electrons. Valence electrons occupy the third orbit of an atom. A metallic bond is created among metallic atoms when some of the valence electrons separate and exist in a free state. The Van der Waals bond is created between neutral atoms. This bond is the secondary bond found in the long chains of large molecules that make polymers. 3. Larger grained metals are more plastic and ductile. The smaller the grain the harder a metal will become; thus, larger grains are much easier to deform. Grain size can be made smaller by more rapid cooling to harden a metal once one is finished shaping it. 4. Thermoplastics and thermosets can withstand a high amount of stress before the strain...
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...Ionic and Metallic Compounds Review Sheet Remember to look over all homework, notes and daily questions. 1. Vocabulary to define a. anion b. cation c. ionic bond substance d. ionic compound ion with a negative charge; formed by gaining electrons ion with a positive charge; formed by losing electrons formed from the transfer of electrons from a metallic substance to a nonmetallic compound containing ionic bonds e. metallic bond metal atoms donate valence electrons to the “sea” of electrons, which are able to move among all of the atoms; metallic cations are attracted to the sea of valence electrons 2. In terms of energy and electron configurations, explain why ionic bonds form. Atoms will gain or lose electrons to form the stable electron configuration of a noble gas; when atoms reach this configuration, they are in a lower energy state, making them stable 3. On the periodic table above, write the charge that an element in each group will form. Column A – 1+ Column B – 2+ Column C – 3+ Column D – skip Column E – 3Column F – 2Column G – 1Column H - skip 4. Based on the periodic table shown: a. elements from columns A and E will combine in which ratio? b. elements from columns B and G will combine in which ratio? c. elements from columns B and C will combine in which ratio? d. elements from columns A and F will combine in which ratio? e. elements from columns C and F will combine in which ratio? A3E BG2 They won’t. A2F C2F3 5. List and describe 3 properties about ionic...
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...First Law of Thermodynamics as the conservation of energy, and the interplay of kinetic, potential, heat and work energy. To describe and apply the Second Law of Thermodynamics from several points of view: randomness, chaos, probability, distribution of matter and energy, energy efficiency. 4. To know that we measure energy only through change, such as with a calorimeter. 5. To use potential energy diagrams to represent changes that take place in reactions 6. To use the terms endothermic and exothermic to describe the entry or exit of heat from chemical systems (and that the opposite change must take place in the surroundings). 7. To know that energy changes in reactions come from changes in chemical bonds, and how they can be estimated from differences in bond energies of bonds broken vs. formed. 8. To express and interpret these changes in potential energy diagrams and apply these skills to the combustion of fuels. 9. To view and describe recent trends in energy source utilization. 10. To give specific details on the composition of coal and its impacts on environmental quality. Assignments: Read §4.1 – 4.5. Recommended exercises: From the above sections, all in-chapter “Your Turn” exercises, and chapter-end problems selected from #1 – 18, 24 - 29 4/30 Outcomes: 1. To describe petroleum as a mixture of hydrocarbons, and how they are separated industrially. 2. To distinguish alkanes from other types of hydrocarbons. 3. To draw examples of straight-chain and branched...
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... a. The solids that the particles are ions. Ex. In sodium chloride, the sodium chloride ions are packed in a lattice and held by strong ionic bonds. b. The solids that the particles are molecules. Ex. An iodine molecule, the molecules are packed in a lattice, and held together by weak forces or covalent bond. Is covalent Solids. Because all ions of sodium chloride are packed together in a lattice and held by strong ionic bonds. So when we mix the sodium and chlorine the compounds are very stable, they have full electron in their outer shells and has opposite charge. Because the ionic bonds are very strong. So it takes a lot of heat energy to break up the lattice and form a liquid. - oxygen - chlorine - water - naphthalene Because actually molecular substances are non metal and when they react together both of them need to gain electrons to reach full shells. They can manage this only by sharing electrons between them, there is a force of attraction to holding them together which call covalent bonds. Ex. - bromine - water - ethanol - ammonia P. 53 Their outer electrons get separated from the atoms. The result is a lattice of positive ions in a sea of electrons. The ions are held together by their attraction to the electrons between them with the strong metallic bonds. Copper and iron a. high compressive strength it means that you have to compress the metal very hard before they deform. b. high...
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...SCH4U – The Chemistry of Covalent Bonding Date_____________________ Orbital Hybridization One of the most influential chemistry books ever written was The Nature of the Chemical Bond by Linus Pauling (1901-1994). Published in 1939, Pauling was awarded the Nobel Prize in 1954. Pauling received a second Nobel Prize for peace in 1962. Pauling made tremendous contributions to the field of chemistry, and was an outspoken activist against war and nuclear weapons. If you consider the energy level diagram for carbon it presents a problem to the VB theory. If bonds are formed between orbitals that contain unpaired electrons, how many bonds does it appear carbon can form? | | 2 | | 1 | | Since Carbon only has 4 different 4 valence electrons, according to the Aufbau principle, the 2s orbital is filled first, and then the 2p sub shell has 2 orbitals with unpaired electrons. This suggests that Carbon can only form 2 bonds. However Carbon is clearly able to form 4 bonds, as evidenced by any carbon compound (e.g. methane, CH4). Linus Pauling suggested that carbon is able to create four unpaired orbitals by promoting one electron from the 2s orbital to the empty 2pz orbital. This hybridizes the one 2s and three 2p orbitals together. This configuration is called ‘sp3’. Like s and p orbitals, the ‘shape’ of sp3 orbitals can be defined by a probability density map of electron location around the nucleus. The shape of a sp3 orbital looks like this: Since carbon...
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...is meant by the idea that it is “the smallest unit of a pure substance that retains properties of that substance”? 3. Understand the nature and arrangement of the subatomic structure of atoms. Where are the subatomic particles found? 4. Why are we concerned about whether atoms are reactive or not? 5. What determines whether a particular element (type of atom) is reactive? 6. Understand the difference between inert elements and those that are reactive and capable of forming chemical bonds. What is the significance of the valance shell of electrons? 7. Why do atoms seek to form bonds with other atoms? How does this correlate with their stability? 8. Understand the nature of ions and ionic bonds. Why is sodium able to ionize, whereas carbon cannot? 9. Why are sodium atoms usually found as positive ions? Why does chlorine ionize to become a negatively charged chloride ion? 10. Understand the nature of covalent bonds. How does the formation of covalent bonds lead to greater stability? 11. Why are the elements C, H, N, O, P, and S so abundant in the...
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...Pure chemical substances are classified as ionic, metallic, covalent molecular and covalent network. In this essay I will describe the nature of each bonding present in these different types of substances and use this to explain the physical properties they exhibit and their structures. Ionic compounds are compounds that are composed of positive and negative ions. An ionic compound is a chemical compound in which ions are held together in a lattice structure by ionic bonds. Usually, the positively charged portion consists of metal (cations) and the negatively charged portion is an (anion) or polyatomic ion. Ions in ionic compounds are held together by the electrostatic forces between oppositely charged bodies. The positive and negative ions in these compounds are thought to be arranged in an orderly three-dimensional lattice. For example, the structure of sodium chloride is shown. In the lattice, each positive sodium ion is surrounded by six negative chloride ions and each negative chloride ion is surrounded by six positive sodium ions. The position of the ions is fixed and apart from vibration about these fixed positions no other movement of the ions occurs in the solid compound. Each ion in an ionic solid is held in the crystal lattice by strong electrostatic attractions to the oppositely charged ions around it. These electrostatic forces between the positive and negative ions are called ionic bonds. Because ionic compounds have high melting points, in other words considerable...
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