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CHEMISTRY Science may have found a cure for most evils; but it has found no remedy for the worst of them allthe apathy of human beings. --Helen Keller Matter Anything that has mass and takes up space. Atoms Fundamental building blocks of all states of matter. Smallest particle of an element that retains the properties of that element. So…What are Atoms made of then? Phases and Transitions of Matter What are they? How many are there? Solid (Ice Cube) This phase of matter has a definite shape and a definite volume. What about the molecules? Do they have any energy? YES! Though it may not seem like it, at the atomic or molecular level, the particles shake or vibrate rapidly in a compact space. Can we change this energy level? Melting This is the transition from a ____________ phase of matter to a ___________ phase of matter. Molecularly, how does this happen? ADD heat energy to excite the particles. Creates enough separation for particles to slide past one another. Liquid This state of matter has a definite volume, but no definite shape. It takes the shape of its container. What about the molecules? Particles have more energy than its solid form, breaking down any organization and allowing room for particles to flow past one another. This is liquid nitrogen being used to make ice-cream. N melts at –210ºC and freezes at -252 ºC . Evaporating This is Review from weather. This is the transition from a ____________ phase of matter to a ___________ phase of matter. Molecularly, how does this happen? ADD heat energy to excite the particles further. Creates enough separation for particles to completely separate from the original source. Boiling Heating liquid to the point at which it begins to evaporate. Turning over of liquid due to heating it to its evaporation point. This state of matter has the volume of the container it is placed it, but no definite shape. It also takes on the shape of its container. What about the molecules? Particles have more energy than its solid and liquid form, allowing them to escape with high levels of energy as a vapor. Gas What happens if we continue to ADD heat energy? The further expansion of the gas. Makes it less dense than the air around it. OR Ionize the particles creating… Plasma Difficult to contain due to the highly ionized particles. Use magnets to keep from touching other surfaces. Deionization To reverse the process, a plasma must lose its charge and become a neutral gas again. How can this Happen? Gas Condensing This is the transition from a ____________ phase of matter to a ___________ phase of matter. Molecularly, how does this happen? Reverse the energizing process. Liquid This is the transition from a ____________ phase of matter to a ___________ phase of matter. Molecularly, how does this happen? Freezing Reverse the energizing process. Solid Sublimation & Deposition Solid to Gas Gas to Solid This transition only takes into consideration two states of matter. When these two changes occur, they completely skip the liquid phase. Sometimes, “sublimation” is used to describe both changes. 8) Review Molecules are disconnected and highly energized. 1) 4) 7) Molecules are able to slide past one another. 2) 5) 6) Molecules are tightly packed and organized. 10) What do we call a highly ionized gas. 3) 9) KMT Kinetic Molecular Theory K – Kinetic – energy of doing work M – Molecular – molecules: tiny structures made up of 2 or more atoms of the same or of different elements. T – Theory – Not a Law (so not set in scientific stone), however, it is the most widely used theory of matter structure and change Does it always have to be a complete phase change? NO! When you wash your hands do you use Hot? Or Cold? Heat Can have an abundance… …a balance… …or a lack thereof. A form of energy that is transferred by a difference in temperature. What can it do? Thermal Expansion Other than a herd of elephants, how do cracks form in sidewalks? Ball and Ring Bimetal Strip Temperature Viscosity Measure of a liquid’s resistance to flow Less More Viscous = ____________ fluid WHY?! More Less Viscous = _____________ fluid The energy of the molecules. Think Maple Syrup Can we then increase or decrease a fluid’s level of viscosity? Pressure What happens to a substance when this is applied? Solid Why will a solid steel ball bounce off a sidewalk? Liquid Gas What are the “bends”? Decompression Sickness Next Slide The volume of a fixed amount of gas (at a constant temperature) is inversely proportional to the gas pressure. Example Inverse Proportion: Inverse of 2 is ½ So we could say: Boyle’s Law 1) More pressure leads to Less volume 2) Less pressure leads to More volume Demo Charles’ Law So we could say: At constant pressure, volume of a gas is directly proportional to temperature. 1) Higher temps lead to Higher volume • Lower temps lead to Lower volume Theoretical temperature at which all molecular movement would cease. Absolute Zero Huh? Means all that moving and shaking we talked about with solids would actually stop. No motion. No e- clouds. Nothing. Has Never Actually Been Achieved! Heat always seems to find a way. Heat is energy. Kinetic energy is therefore generated. Superconductivity! Review 1) What is the theory widely accepted for explaining the transitions from one state of matter to another at the atomic level? 2) What is a form of energy that is transferred by a difference in temperature. 3) In the ball and ring experiment: a) What happened when the ball was heated? b) What happened when the ball was cooled? 4) How do the answers to #3 explain cracks in a sidewalk? 5) True of False. Temperature scales are only different in name. 6) By heating a liquid, does it become More or Less viscous? 7) According to Boyle’s Law, when pressure is ________________, the volume of a gas is decreased. 8) According to Charles’ Law, when the temperature of a gas is increased, the volume of space the gas can fill ________________. 9) What do we call the theoretical temperature at which all molecular/atomic movement would cease? Bonus: What is an explanation as to why this temperature is theoretical? Elements Basic materials that create molecules, compounds, mixtures, etc… These are the most basic materials known. They cannot be broken down into anything but the atomic particles that define them. ELEMENTal Questions Get it…element-al. Element. Get it. 1) How many elements do we know of ? 2) Are they all naturally occurring? 3) How are they different? Answers 1) 117 have been observed as of 2008 2) No. 92 are naturally occurring, however the rest are synthetically produced. Often this happens during nuclear reactions. 3) You tell me. Dalton Rutherford Early Models Thompson Louis de Broglie Atoms These tiny particles are the building blocks of all matter. They are the smallest material that can exist and still retain the properties of what it is they make up. The three particles of an atom: 1) Proton 2) Neutron 3) Electron Proton These Positive particles are found in the nucleus of the atom. They have an atomic mass unit (amu) of 1. They are the identifiers of each element in the periodic table. They are made up of smaller particles called quarks. Though this is known, it is still vague as to how the quarks combine to create (if they even do) the positive charge of the proton. Neutron Is Neutral. In the Nucleus. Neu-Neu-Nu! Neutrons are sub-atomic particles that carry no net charge. They too are equal to a mass of 1 amu, and are also found in the nucleus. Like protons they are made up of quarks, however the combination does not seem to create a charge. They play a key role in finding the atomic mass and defining isotopes. Nucleus Center of an atom that contains particles that make up the atomic mass. Protons and neutrons stay together as a central mass. This central mass is responsible for keeping the electrons in orbit around it. Electron Orbit There are several layers of electrons around the nucleus. Why? Why can’t they all just move around at random? Electron Energy Levels Each level can contain only a specific maximum amount of electrons. They can hold less, and shells without electrons may reduce in size. An atom could lose all electrons, but it would not really be considered an atom if it lost all of its electrons. Why does the letter designation start with the letter K? Valence Electrons These are the electrons found in the outermost energy level of an atom. They are responsible for the giving, taking and sharing of electrons which cause chemical reactions to take place. The ability for these to be gained or lost is relevant to the proximity to the nucleus. Review 1) What do elements help to make up? 2) What are the elements made up of? (1 word, 5 letters) 3) What are the 3 particles that make up the answer to #2? 4) What are their charge properties? 5) What are their locations in the answer to #2? 6) How are the particles on the outside of answer #2 arranged? 7) What do we call the particles responsible for chemical reactions. (2 words) 8) Why are these reactions important? (1 sentence) Organized table of elements known to us that exist in the Universe. Some are gasses, some are liquids, most are solids (metals). Some are explosive, some are pretty, some are poisonous, some are useful. Some we find in nature, some we extract from natural things, some we make ourselves. When combined, there becomes an infinite list of creations that we enjoy, eat, study, take for granted, run into, cut down, grow…hopefully that is enough and you get the point. How do we make sense of such simple, yet complex materials? Periodic Table Look around the room. Are they different? Dmitri Mendeleev First to create a feasible means of organizing the elements. Allowed for the discovery of unknown (at the time) elements by using the atomic masses. Chemical Symbols When officially recognized as an element a symbol of 1 or 2 letters is used. One is always capitalized, and if a second letter is used it will be lower case. 3 letters are assigned as a element is being studied. The names and symbols represent Latin name of the element number. Atomic Number This is the number that identifies one unique element from another. When looking at the periodic table, you will typically see this number above the symbol. However, you should always check to see if this is true by looking for the smaller number. Except for Hydrogen, the Atomic numbers of elements are always less than the Atomic mass. Atomic Number = Number of Protons in the Nucleus The weight or mass of an atom of an element calculated by the sum of the particles of the nucleus. What are the particles of the nucleus? Protons + Neutrons = Atomic Mass Atomic Mass Atomic Equations Ok…here are some equations I will expect you to know and know how to use. 1) Atomic # = # of P+ 2) At. Mass = Protons + Neutrons 3) At. Mass – Atomic # = Neutrons 4) At. Mass – Neutrons = Atomic # 5) In equilibrium the #P+ = #e- Group/Family Number Groups are signified by both numbers and letters. The A group tells you the number of valence e-. Easier to count. You just count the columns. Can still tell you the number of valence e-. Do you see the pattern? Group and family number will not tell you how many electrons are in all the shells. So what do we do? 2n² Ion What happens when electrons are lost or gained? Atom becomes charged either _________or _________. So what are these ones? Charge Reactions By now, you should know this, but do you know its importance as far as Chemistry is concerned? These are the rows Go left to right . . There are 7 periods . These signify the number of electron energy shells that exist in an atom of an element. Coinkydink! The maximum number of shells an atom can have is 7! Period Number Alkali Metals YES!! For crying out loud, it’s all significant! How many electrons do these have in the valence shell? Is this significant? Having only 1 valence electron means it is very, very, very, very, very, very…what? REACTIVE! Which of these is the MOST reactive? WHY? How many valence electrons do these have in the valence shell? Is this significant? YES!!! Having 2 valence electron means it is still reactive. Just less so than the Alkali Metals. Which of these is the MOST reactive? WHY? WHY? Alkaline Earth Metals As you can see, these make up the majority of the Periodic Table. They are all solids except for Mercury, which is liquid at room temperature. M E T A L S These metals mark the movement from metallic to non-metallic elements. As you move to the right, properties begin to lesson, until you reach the metalloids. Transition Elements (Metals) Metalloids The stair step of the Periodic Table. These elements create the true boundary line between metals and non-metals. They contain only some properties of metals, while sharing some of the properties of non-metals. Nonmetals Well…they’re not metals. Actually, a lot of them are gasses. Ones a liquid. Ok, Ok…These are the elements that make up the composition of the atmosphere. This group also contains the only other liquid that is listed on the periodic table. Not to mention Carbon which is found in all living things. That might be important. Halogens How many valence electrons do these have? These are the non-metal counterparts to Alkali Metals. Is this relevant? Of Course It Is!!!! What does that mean? To achieve a nice stabilizing number of valence e-, they only need to gain 1 move e-. Inert (Noble) Gases These are the Snobs of the Periodic Table. Why? They are not quick to combine with any of the other elements. Why? How many valence e- do they have? Synthetics (Artificially Made) What does this mean? We make them through nuclear fusion and neutron absorption. These elements are thought to have been present when Earth formed, but have since decayed. Review 1) What on the periodic table is equal to the sum of the particles in the nucleus? 2) What is THE ID tag for each element? 3) What is atomic equilibrium? Why is this important? 4) How did Mendeleev first organize a periodic table? 5) Columns are called what two things? What does this tell us? 6) What are rows called? What does this tell us? 7) What equation do we use to find maximum electrons in a shell? 8) What are the most reactive metals? Non-metals? Why? 9) What are the least reactive elements called? 10) What are metalloids? 11) What are synthetic elements? Bonus: How are synthetics made? Radiation Energy transmitted in the form of rays or particles. Can be helpful and harmful. Are you familiar with this? Any experience with it? The Crookes tube was use to test the properties of electricity across a void. Using a vacuum tube in which cathode rays (electrons) were introduced, Crookes demonstrated how those electrons would transmit from one side of the tube to the other creating a connection. He used thallium as a conductor. (Green glow) Sir William Crookes Alpha Particle Cluster of particles ejected from the nucleus of radioactive material. Consists of 2 protons and 2 neutrons. Beta Particle Gamma Ray Electrons formed from radioactive decay of an element in which a neutron converts to a proton and an electron. The most energetic photons of the electromagnetic energy spectrum typically released from the nucleus when beta particles are created. Well…what do they look like? These are two or more atoms of the same or of different elements that are chemically bonded together. These are what create…. Things. M o l e c u l e s + = Solution + Fe + Al + = Mixture = Compound Binary Compounds Chemical compounds that are composed of only ______ elements. Ionic Bond Bond created between two elements, where the valence electron from one element is contributed to the other, causing now positively and now negatively charged particle to be attracted to one another. They share the valence electrons. The cooperate. Co-valent. Covalent Bond Polar Covalent Bond Bonds Sharing of valence electrons creates polar ends to the molecule. Nonpolar Covalent Bond This is the process in which the original substances go through a transformation when they are combined, resulting in a new material being made. Reactions can at time absorb energy, and at times release energy. Reaction Does the new substance (product) have to retain the properties of the original? Sodium Chlorine Stable Ok… There are several ways to describe this: 1) A balance between proton and electron numbers. 2) Inner electron shells are full. 3) 8 electrons present in the outermost (valence) shell. 4) Non-radioactive. Unstable No Jokes Please. 1) Elements Decomposing on their own. 2) Highly or violently reactive elements such as alkali metals and halogens. 3) Decaying with relatively short lifetime. Used of subatomic particles. 4) Radioactive. Nuclear Reaction Fusion Nuclei from atoms are merged together to form another element. In the process energy is released. Yes.. It is also a car. Not an acceptable answer on any work done for me in class. Fission Process in which a nuclei of a dense atom is bombarded with neutrons, causing a division so two different elements are created and energy is released. Review 1) What are the primary components of alpha particles? 2) What is the key particle associated with beta particles? 3) When solid is absorbed into a liquid, it is described as what? 4) When two substances are combined, yet their original properties are still present, and they can be physically separated, it is what? 5) When two substances are combined creating a new substance, it is called what? 6) All the bonds discussed create what building block of matter? 7) What are some ways to describe a material as being stable? 8) What is the difference between fusion and fission? 9) How could these two nuclear reactions be used beneficially? Unit Review Outline I. States of Matter II. KMT and Thermal Dynamics III. Elements and the Periodic Table Paragraph Response Question