...Atoms, Molecules, and Elements Michelle Faunce-Carroll CHM/110 - INTRODUCTORY CHEMISTRY BSDT1HX1M4 WILLIAM DE VORICK AUGUST 10, 2015 Atoms, Molecules, and Elements Atoms, Molecules, and Elements are a part of everything we do in life. Most people don’t recognize the extent that chemistry plays in our everyday lives. From the foods we eat, to the products we use for cleaning ourselves, our homes, our cars; atoms, molecules, and elements are a part of all of these things. Dmitri Mendeleev began studying elements in the early 1800’s. Through his learnings he found that elements are sortable, have similar properties, and are even predictable. In addition to this his research also led to his coming up with the periodic table. Thanks to Dmitri Mendeleev we can now know the way molecules are formed. Because of this we know the charge of the elements, which in turn helps us to know how they will react with each other when combined, we are able to predict if this will be a good or bad reaction. Grouping elements into families was first taught by Dmitri Mendeleev. He began by studying their atomic weight, charge, and reactivity. And then grouping the elements with similar properties within the same family. Within these families we can look at how they would react with other elements on the periodic table. Take hydrogen for example when this is paired with oxygen to form H2O, you have to have 2 hydrogen...
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...Atoms are the smallest entities which resemble the properties of an element and cannot be broken down into smaller parts. Molecules are formed when two or more atoms are combined. This formation can happen in a variety of ways. When two oxygen atoms join O2 is formed, and when three oxygen atoms join O3 or ozone is formed. Both of these have different properties. Different atoms can also combine to form molecules. Hydrogen combines with sulfur to form H2S and hydrogen and oxygen also combine to form H2O. Dmitri Mendeleev’s Periodic table is based on atomic weight, whereas, the modern periodic table keeps the atomic number as the base. An atomic table arranges elements from left to right in a row with the atomic number and properties gradually changing. The elements on the next row will actually exhibit similar properties as the ones above or below it. This provides an example of the periodicity nature of the elements. The columns of different elements in a period have the same or very similar properties. The properties of the elements change gradually as the columns move down through the periodic table. Atoms in similar families, such as H2S and H2O, exhibit both similar properties and molecular structure. This shows periodicity in both the molecules and the individual atoms. Alkali metals contain a single electron in their outer shell rendering them highly reactive. This allows them to be ready to donate this single electron to form molecules with substances...
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...Atoms, Molecules, and Elements Atoms, Molecules, and Elements Take a look out the window. Consider that everything that you can and cannot see is composed of atoms. Some of these may be bonded with other atoms to form molecules. All matter is composed of atoms that are too small to see. Weather the matter is liquid, gas or solid, pure or a mixture. It is the basis for elements that make up what we know today as our periodic table. Demetri Mendeleev was trying to organize the elements into a table by weight when he noticed that as the weights increase occasionally the properties of one element would resemble those of an element he already listed so he placed these elements in a column under the ones they resembled chemically ( Capri, PhD, 2003). Each chemical in the vertical rows on the periodic table are considered families or groups because they have properties that are similar to each other. All the chemicals in group 1A of the periodic table are considered alkali metals. Alkali metals are similar in that each of them has only one atom in the outermost shell and they are very reactive when combined with other elements. All elements in column 7A are halogens. Halogens are also highly reactive oxidizing agents that are called “salts”. All halogens have 7 electrons in their outer shells, giving them an oxidation number of -1 ( Bodner Research Web, n.d.). Noble gases can be found in Column 8A. These elements are all considered to belong in this column because they are all...
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...Atoms, Molecules, and Elements Paper Candace Jefferson March 8, 2016 Charles Chau Chem/110 Atoms are the smallest particles and have the resemblance properties of an element they cannot be broken down and this is considered the building blocks. The atom has a nucleus that is surrounded by electrons. An atom can be negatively or positively charged just depends on the surrounding particles. Molecules are formed when there is a group that is formed and then they are bonded together. It will all depend on how they are bonded that will determine the type of element that will be formed. The periodic table was created by a Russian chemist by the name of Dimitri Mendeleev. He created this table so that everyone would be able to see all of the things that he is able to see. This table is used all through the school system helping people all over the world understand chemistry and making it a lot easier. He wanted it to be organized in a way so that it will be in a group separating certain characteristics. The main purpose of the periodic table was to show the chemical properties explaining the similarities and the differences between everything that he would have on the periodic table. “Mendeleev...
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...Atoms, Molecules, and Elements Paper Carolyn R. Slaughter CHM/109 October 12, 2014 Jodi Wolf Atoms, Molecules, and Element Paper Each column within a periodic table is called a family or group of elements. The Group 1A elements are called alkali metals and they are all reactive metals. The Group 7A elements called halogens are very reactive nonmetals. The Group 8A elements are called noble gases. The noble gases are inert (or unreactive) compared to other elements. Alkali metals and halogens are both reactive. They react spontaneously with water, oxygen and other elements. The elements form a strong base s that is capable of neutralizing strong acid and then reacting. Halogens and alkali have high electro negativities and a large number of valence electrons. These two elements display physical properties which makes them highly reactive when combined together. Noble gases are chemically stable and will not combine with other elements to form compounds (Tro, 2009). When comparing properties of molecules formed from atoms in similar families such as H2S and H2O, there is a similarity of properties in the elements. Both display similar molecular makeup and properties. First they both have been composed of two hydrogen atoms. H2S is a gas formed from 2 hydrogens, water, and sulfate. H2O remains liquid because of its electronegativity it is 2 hydrogens and oxygen, which is water. The trends and patterns of the periodic table were organized by Mendeleev. All elements in...
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...ATOMS AND MOLECULES - The properties of matter depend on the properties of atoms and molecules from which it is made. Laws of chemical combination (I.) Law of conservation of mass: It states that mass can neither be Created nor destroyed in a chemical reaction. - It means that in a chemical reaction, the total mass of products is equal to the total mass of reactants. There is no change in mass during a chemical reaction. (ii) Law of constant proportions: In a chemical substance the elements are always present in definite proportions by mass. - Dalton’s atomic theory - The postulates of his theory are as follows: (I.) All matter, whether an element, a compound, or a mixture is Composed of very tiny particles called atoms. (ii.) Atoms are indivisible particles, which cannot be created or Destroyed in a chemical reaction. (iii.) Atoms of a given element are identical in mass and chemical Properties. (iv.) Atoms of different elements have different masses and chemical Properties. (v.) Atoms combine in the ratio of small whole numbers to form compounds. (vi.) The relative number and kinds of atoms are constant in a given compound. - Drawbacks of Dalton’s atomic theory: (I.) Atoms were indivisible according to Dalton. We now know that under special circumstances, atoms can be further divided into still smaller particles called electrons, protons and neutrons...
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...of atoms and molecules. Explain at a level of detail Dmitri Mendeleev would have understood how halogens and alkali metals are extremely reactive, whereas noble gases are not reactive. Compare properties of molecules formed from atoms in similar families; for example, H2S versus H2O. Explain what is meant by the electronic structure of atoms. How does knowing the electronic structure of atoms aid chemists in predicting chemical reactions? Periodic Table is designed to help us understand how elements are going to react to each other and also gives us the breakdown of how many atoms are in each element. This chart also helps us to identify metals, liquids, and gases. This chart shows us the atomic mass and structure of each element. Knowing this information allows us to determine which elements can bond and interact with each other. Alkali metals and halogens can form ionic bonds easily which involves the transfer of an electron from an atom of metal forming a positively charged species, to an atom of non-metal forming a negatively charged species. These two species interact electrostatically and form one of the two extreme forms of bonding; covalent bonding is the other extreme form (Kostiner & Jespersen, 2003). Electronic structure is another piece of important information that you will find on the Periodical Table, this is the atomic number and it will tell you how many atoms make up the element. Alkali Metals and Halogen We know that there are some stable elements and...
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...Atom: the smallest particle of an element that has properties of an element Atomic Theory: Greek philosopher DEMOCRITUS * Atoms can’t be broken into smaller pieces * In any one element, all atoms are exactly alike * Atoms of different elements are different * Atoms of 2 or more elements can combine to form compounds * Atoms of each element have a unique mass * The masses of the elements in a compound are always in constant ratio Bohr Theory: Danish physicist NEILS BOHR * Electrons are arranged in definite shells or NRG levels, considerable distance from the nucleus * Electron configuration: how electrons are arranged * # of electrons = the atomic # of atoms Sir James Chadwick: 1932 * Discovered in the nucleus another particle, neutron * Neutron has same weight as the proton * Neutron has no electrical charge * Nucleus is made up of protons and neutrons * # of protons is = to # of electrons, which is the atomic # of atom Atoms & Molecules * Atoms combine & arrange to form different compounds & molecules * Molecule: 2 or more atoms that are joined together chemically to act as a single unit * Chemical Bond: is the force that holds atoms together * Compound: 2 or more different atoms joined together chemically * All compounds are molecules, but not all molecules are compounds Ex: Oxygen gas = O2 is a molecule, not a compound (both atoms are alike) Water= H20 is a molecule &...
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...Name Lab Section Date The Mole Concept and Atomic Weights Text Reference: Tro, Chemistry: Structure and Properties Section 2.8 - Atoms and the Mole: How Many Particles? Section 1.9 – Atomic Mass: The Average of an Element’s Atoms The purpose of this activity is to better understand the concepts of relative atomic mass, counting by weighing and the mole. Per cent composition and average atomic mass are included. Part I. Relative Atomic Masses and the Mole – Early Method When John Dalton proposed his atomic theory, he stated that the atoms of each element had a characteristic mass. He carried out experiments to determine the relative atomic mass of each element. To do this, he had to establish a standard because a single atom was too small to weigh. The standard he chose was that the mass of hydrogen would be set equal to 1.000. In a simple experiment, Dalton would measure the grams of an element such as sulfur that reacted with 1.00 gram of hydrogen. For sulfur, the reacting mass was found to be 32.0 grams, and so 32.0 was the relative mass of sulfur with respect to the standard hydrogen. (Note: The current standard for atomic mass is the most abundant isotope of carbon, C-12, with an assigned mass of exactly 12.000 amu.) The following activity will demonstrate how the relative mass method works. 1. Weigh five of the red color balls to three decimal places. Be sure to tare out the mass of the plastic cup. Record the mass in the table below. 2. Weigh five...
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...Chapter 5: Properties of Matter Matter is anything that has a mass and takes up space. The particle theory of matter is a theory that describes the composition and behavior. Matter can be many up of many different particles or only one. A pure substance is a type of matter that consists of only one type of particle. Then there are mixtures that are made up of at least two different types of particles. There are two different types of mixtures; mechanical mixtures and solutions. A mechanical mixture is a mixture in which the substances in it are distinguishable from each other, either with the unaided eye or a microscope. A solution looks like a pure substance but it contains more than one type of particle. Alloys are when two or more metals are mixed together. A physical property is a characteristic of a substance that can be determined without changing the composition of that substance. A qualitative physical property is not measured and includes hardness, malleability and electrical conductivity. Quantitative physical properties are measured and include temperature, height and mass. A physical change is a change is which the composition of the substance remains unaltered and no new substances are produced Examples of physical change are a change of size or shape, a change of state, and dissolving. A chemical property is a property of a substance that describes its ability to undergo changes to its composition to produce one or more new substances. A chemical; change is a...
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...Concepts: Matter Matter – anything that occupies space and has mass. Fundamental Particles of Atoms (Historical Point of View) John Dalton (1808) – atomic theory 1. Atoms – small indivisible particles. 2. Atoms – neither created nor destroyed. 3. Atoms – chemical reactions result from combination / separation of atoms. J. J. Thomson (1897) 1. Electrons – negatively-charged particles. 2. Atoms – positively-charged sphere. Ernest Rutherford (1911) 1. Atoms – consists of a positively-charged nucleus with a cloud of electrons surrounding nucleus. 2. Protons – positively-charged particles. Niels Bohr (1913) 1. Electrons – surrounding the nucleus (orbit). James Cadwick (1932) 1. Neutrons – electrically neutral subatomic particles. 2. Neutrons – mass almost the same with a proton. 3. Nucleus of an atom – consists of protons and neutrons. Modern Atomic Model 1. Nucleus of an atom – consists of protons and neutrons. 2. Electrons – moving around the nucleus (orbits / electron shells/ quantum shells) Atoms Atom – smallest particle of an element. Relative atomic mass (Ar) - (an element) average mass of one atom of the element relative to 1/12 times the mass of one atom of carbon-12. = (average mass of one atom of the element) / (1/12 x mass of one atom of C-12) Or = 12 x [(average mass of one atom of the element) / (mass of one atom of C-12)] Cations – positively-charge ions. Example: H+, K+, NH4+ and Mg2+ Anions – negatively-charge...
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...Multiple-Choice Questions 1) About 25 of the 92 natural elements are known to be essential to life. Which four of these 25 elements make up approximately 96% of living matter? A) carbon, sodium, chlorine, nitrogen B) carbon, sulfur, phosphorus, hydrogen C) oxygen, hydrogen, calcium, sodium D) carbon, hydrogen, nitrogen, oxygen E) carbon, oxygen, sulfur, calcium Answer: D Topic: Concept 2.1 Skill: Knowledge/Comprehension 2) Trace elements are those required by an organism in only minute quantities. Which of the following is a trace element that is required by humans and other vertebrates? A) nitrogen B) calcium C) iodine D) sodium E) phosphorus Answer: C Topic: Concept 2.1 Skill: Knowledge/Comprehension 3) Three or four of the following statements are true and correct. Which one, if any, is false? If all the statements are true, choose answer E. A) Carbon, hydrogen, oxygen, and nitrogen make up approximately 96% of living matter. B) The trace element iodine is required only in very small quantities by vertebrates. C) Virtually all organisms require the same elements in the same quantities. D) Iron is an example of an element needed by all organisms. E) All of the other statements are true and correct. Answer: C Topic: Concept 2.1 Skill: Knowledge/Comprehension 4) Which of the following statements is false? A) Atoms of the various elements differ in their number of subatomic particles. B) All atoms of a particular element have the same number of protons in their nuclei...
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...Introduction to Chemistry I (MAE1106) Chapter 1: Properties, Measurement and Units Matter: All things we can see, or touch, whether books, pencils, telephones, or people as they have some thing in common. They are all composed of matter which is defined as anything that takes up space and has mass. Matter is generally considered to be a substance (often a particle) that has rest mass and (usually) also volume. Mass and weight are not really the same. The mass of a body is a measure of its resistance to a change in its velocity. Weight refers to the force with which an object of a certain mass is attracted by gravity to the earth or other body that may be near such as moon. The volume is determined by the three-dimensional space it occupies, while the mass is defined by the usual ways that mass is measured. Matter is also a general term for the substance of which all observable physical objects consist Properties of Substances Physical (Properties and Changes) A physical property is one that is displayed without any change in composition. (Intensive or Extensive) 1. Intensive: A physical property that will be the same regardless of the amount of matter. density: m/v • color: The pigment or shade • conductivity: electricity to flow through the substance • malleability: if a substance can be flattened • luster: how shiny the substance looks 2. Extensive: A physical property that will change if the amount of matter changes. • mass: how much...
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...STUDENT STUDY GUIDE FOR 8TH GRADE CHEMISTRY Welcome to chemistry. Chemistry is the science of matter and its interactions. Everything around you is made of atoms – atoms and their chemical combinations, molecules. Everything you can see, touch, smell, and taste is made up of chemicals. So, the science of chemistry is a very wide ranging science. Parts can concentrate on how interactions of atoms and molecules allow the nerves in your body to conduct electrical signals. Other parts might concentrate on analyzing clues left by a burglar in order to help the police solve a crime. Still, other parts of chemistry might be involved in making new polymers that might be used by the fashion industry to make more colorful and longer wearing fabrics. If you have access to a computer and the internet, there are a number of excellent tutoring sites to help students gain a better understanding of chemistry. One of the better sites for middle school students Is: www.chem4kids.com/ This site is written at middle school level and has a number of on-line tests that you can use to check your understanding of the material. Several other good internet sites are: http://chemistry.about.com/od/chemistry101/Chemistry_101_Introduction_to_Chemistry.html - Chemistry 101 - a collection of articles and on-line help sites in chemistry http://library.thinkquest.org/10429/low/indexl.htm - ChemWeb on line - an introductory chemistry course on line http://library.thinkquest.org/2923/ - Chemistry...
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...SQ 1-1 Define the term ‘element’, and state the number of naturally occurring elements. Identify by name and the chemical symbol the 4 most abundant elements found in the human body. Identify by name and chemical symbol at least 4 trace elements. An element is the simplest form of matter and cannot be broken down into simpler substances in a chemical reaction. Elements have unique properties. There are 91 natural occurring elements, 24 of these elements play a normal physiological role in humans. The 4 most abundant elements found in the body are oxygen (O), carbon(C), Hydrogen (H) and Nitrogen (N). there are 8 major or less elements in the body include calcium(Ca), phosphorus(P), sulfur(S), potassium(K), sodium(Na), chlorine(Cl), Magnesium(Mg) and iron(Fe). Trace elements account 0.7% of body weight and play a vital roles in physiology, they include, cobalt (Co), copper (Cu), fluorine (F), and iodine (I) Define the term ‘atom’. Discuss the structure of an atom including A) the name of the 3 major types of subatomic particles, B) the electrical properties of each of these subatomic properties, and C) the arrangement of these subatomic particles in the atom including a brief description of electron shells or energy levels. An atom is the smallest unit of an element which consists of a proton (P), neutron (n) and an electron (e). Protons are positively charges, electrons are negatively charged and neutrons have no charges i.e. are neutral. Both the proton and neutron are...
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