21. CHEMISTRY I: ATOMS AND MOLECULES d) Ne; e) N; The chemical bond between water molecules is a a pH of 7 has _ timesmore H ions than a bond formed when electrons are shared between atoms is a http://www.emc.maricopa.edu/faculty/farabee/BIOBK/BioBookCHEM1.html

CHEMISTRY I: ATOMS AND MOLECULES Table of Contents Atoms Electrons and energy Chemical Bonding Chemical reactions and molecules ... Back to Top Most of the Universe consists of matter and energy . Energy is the capacity to do work. Matter has mass and occupies space. All matter is composed of basic elements that cannot be broken down to substances with different chemical or physical properties. Elements are substances consisting of one type of atom , for example Carbon atoms make up diamond, and also graphite. Pure (24K) gold is composed of only one type of atom, gold atoms. Atoms are the smallest particle into which an element can be divided. The ancient Greek philosophers developed the concept of the atom, although they considered it the fundamental particle that could not be broken down. Since the work of Enrico Fermi and his colleagues, we now know that the atom is divisible, often releasing tremendous energies as in nuclear explosions or (in a controlled fashion in) thermonuclear power plants. Subatomic particles were discovered during the 1800s. For our purposes we will concentrate only on three of them. The

22. Atoms, Ions And Molecules And Their Structure First Previous Next Last Index Text. Slide 6 of 9. http://www.chem.neu.edu/Courses/1131Tom/Lecture2/sld006.htm

23. COTW02 Chem 12 Concept of the Week. Chapter 2 atoms, molecules, and ions. TextbookChemistry, Fourth Edition Steven S. Zumdahl Houghton Mifflin Company, 1997. http://www.yk.psu.edu/~jhb3/cotw02.htm

24. COTW10 Since the wavelength of xrays is on the same order of magnitude as the distancesbetween the atoms, ions, or molecules in a crystal, the x-rays are diffracted http://www.yk.psu.edu/~jhb3/cotw10.htm

25. Compounds 1 Selective Permeability. I.. Diffusion. The term diffusion refers to themovement of atoms, ions and molecules down a concentration gradient. http://www.specialedprep.net/MSAT SCIENCE/Cellular Biology/compounds1.htm

Molecular Biology and Biochemistry 6.1 Molecular Biology and Biochemistry a. Demonstrate that a small subset of elements (C, H, N, P, S, H) makes up most of the chemical compounds in living organisms by combining in many ways b. Recognize and differentiate the structure and function of molecules in living organisms, including carbohydrates, lipids, proteins, and nucleic acids c. Describe the process of protein synthesis, including transcription and translation d. Compare anaerobic and aerobic respiration ... e. Describe the process of photosynthesis in terms of light-induced reactions and the Calvin Cycle 1. Demonstrate that a small subset of elements (C, H, N, P, S, H) makes up most of the chemical compounds in living organisms by combining in many ways The drawing of the periodic table above shows all the stable atoms discovered to the present. It is interesting to note that of all the atoms in this table only six are those atoms that make up all living things. They are in red above...

26. Shapes Of Molecules And Ions Containing Single Bonds Two species (atoms, molecules or ions) are isoelectronic if they have exactly thesame number and arrangement of electrons (including the distinction between http://www.chemguide.co.uk/atoms/bonding/shapes.html

SHAPES OF MOLECULES AND IONS This page explains how to work out the shapes of molecules and ions containing only single bonds. If you are interested in the shapes of molecules and ions containing double bonds, you will find a link at the bottom of the page. The electron pair repulsion theory The shape of a molecule or ion is governed by the arrangement of the electron pairs around the central atom. All you need to do is to work out how many electron pairs there are at the bonding level, and then arrange them to produce the minimum amount of repulsion between them. You have to include both bonding pairs and lone pairs. How to work out the number of electron pairs You can do this by drawing dots-and-crosses pictures, or by working out the structures of the atoms using electrons-in-boxes and worrying about promotion, hybridisation and so on. But this is all very tedious! You can get exactly the same information in a much quicker and easier way for the examples you will meet at A'level. Warning: This method won't work without some modification for many ions containing metals, and no simple method gives reliable results where the central atom is a transition metal. The method will, however, cope with all the substances that you are likely to meet in this section of the syllabus. When you deal with transition metal chemistry, you will be expected to know the shapes of some ions formed by transition metals, but not to work them out. At that point, learn the ones your syllabus wants you to know.

27. Electronegativity find this sort of bond in, for example, H 2 or Cl 2 molecules. ions have been formed bond,the electrons are held on average exactly half way between the atoms. http://www.chemguide.co.uk/atoms/bonding/electroneg.html

ELECTRONEGATIVITY This page explains what electronegativity is, and how and why it varies around the Periodic Table. It looks at the way that electronegativity differences affect bond type and explains what is meant by polar bonds and polar molecules. If you are interested in electronegativity in an organic chemistry context, you will find a link at the bottom of this page. What is electronegativity Definition Electronegativity is a measure of the tendency of an atom to attract a bonding pair of electrons. The Pauling scale is the most commonly used. Fluorine (the most electronegative element) is assigned a value of 4.0, and values range down to caesium and francium which are the least electronegative at 0.7. What happens if two atoms of equal electronegativity bond together? Consider a bond between two atoms, A and B. Each atom may be forming other bonds as well as the one shown - but these are irrelevant to the argument. If the atoms are equally electronegative, both have the same tendency to attract the bonding pair of electrons, and so it will be found on average half way between the two atoms. To get a bond like this, A and B would usually have to be the same atom. You will find this sort of bond in, for example, H

28. Intense Laser Interactions With Atoms Intense Laser Interactions with atoms, ions and molecules. Our experimentsuse very short (10 14 s) laser pulses which are focussed http://www.qub.ac.uk/mp/ampr/projects/laser/laser.htm

Atomic and Molecular Research Division Intense Laser Interactions with Atoms, Ions and Molecules Our experiments use very short (10 s) laser pulses which are focussed down to intensities which are trillions of times brighter than the Sun. In such an extreme environment, we investigate how electrons are ripped from atoms/ions and how molecules fragment. Prof. Ian Williams Atomic Ions in Femtosecond Laser Pulses Dr. Jason Greenwood Negative Ions in Ultrashort, Intense Laser Fields Home Members Research Projects Ph.D./Job Opportunities ... Links This page is maintained by Jason Greenwood Last updated: 03/24/03.

29. Double Award - Science For GCSE 3. atoms, ions and molecules. In different substances, the particlesare either atoms, molecules or ions. atoms, ions and molecules http://www.gcsesciencedoubleaward.co.uk/c14.htm

Menu Chapter 1 Chapter 2 Chapter 3 Chapter 4 ... Chapters Chapter 14 Particles, reactions and equations Click this "Print" button to print this page: Classifying materials Materials and substances can be classified in different ways. As naturally-occurring and man-made. As elements, compounds and mixtures. As solids, liquids and gases. Solids liquids and gases are called the three states of matter . We can change the state of a substance by heating it or cooling it. Different substances change state at different temperatures. The kinetic theory of matter tells us that substances are made up of incredibly small moving particles. Small particles move faster than larger particles at the same temperature. As the temperature rises, the particles have more energy and move around faster.

30. Definition Of Terms tool, which enables chemists armed with nothing more than a table of atomic weightsand a balance to determine the number of atoms, ions or molecules in a http://chemed.chem.purdue.edu/genchem/topicreview/bp/ch3/massmol.html

Definition of Terms Atomic Mass Isotopes Atomic Weight The Mole ... Converting Grams Into Moles Atomic Mass The units in which the mass of an atom are expressed are atomic mass units . At one time, the lightest atom was assigned a mass of 1 amu and the mass of any other atom was expressed in terms of this standard. Today atomic mass units are defined in terms of the C isotope, which is assigned a mass of exactly 12.000... amu. Isotopes Isotopes are atoms of the same element with different numbers of neutrons, such as the Ne and Ne isotopes of neon or the Cl and Cl isotopes of chlorine. Atomic Weight The atomic weight of an element is the weighted average of the atomic masses of the different isotopes of an element. Naturally occurring carbon, for example, is a mixture of two isotopes, C (98.89%) and C (1.11 %). Individual carbon atoms therefore have a mass of either 12.000 or 13.03354 amu. But the average mass of the different isotopes of carbon is 12.011 amu. Molecular Weight The molecular weight of a compound is the sum of the atomic weights of the atoms in the molecules that form these compounds.

31. Unit 11 Protons, neutrons, and electrons come together to form atoms, ions,and molecules. The atoms, ions, and molecules form the astronomical http://www.phyast.pitt.edu/Resources/Education/classes/astro88/0088u11.htm

Unit 11 The Basics of Matter and Radiation OVERVIEW The purpose of this unit is mainly to introduce the definition of terms that modern scientists often use to discuss matter and electromagnetic radiation. LEARNING OBJECTIVES At the end of this unit you should be able to: 1. Understand the definitions for the building blocks of matter and how smaller units of matter combine to form larger units. 2. Explain the relationship between energy, wavelength, and frequency in electromagnetic (EM) radiation. 3. List the types of EM radiation in order of increasing or decreasing energy. 4. List the types of visible light in order of increasing or decreasing energy. 5. Explain how continuum, emission, and absorption line spectra are produced. 6. Explain how the Doppler effect (Doppler shift in energy/wavelength/frequency) is produced. IMPORTANT TERMS AND CONCEPTS Proton Neutron Electron Photon Graviton Elementary particle Atom Ion Molecule Mass Charge Ionized gas Plasma Electromagnetic (EM) radiation Light Energy Wavelength Frequency Gamma rays X-rays Ultraviolet (UV) radiation Visible radiation (red, orange, yellow, green, blue, indigo, violet)

32. Atoms, Ions And Molecules 2Sep-03 http://ola4.aacc.edu/jpjendrek/CHE111/ch02-2.htm

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33. Chapter 2 Ions And Molecules Chapter 2 ions and Biomolecules. Objectives. 1. Identify the smallest unitsof mass in the body – atoms. 2. Understand the formation of molecules. http://main.uab.edu/show.asp?durki=63986

34. Learnchem.net: Atoms Tutorial So there are 10 neutrons. Easy. molecules and ions. Compounds aremade up of two or more atoms held together in some way. Although http://www.learnchem.net/tutorials/atoms.shtml

Main AP Chemistry News About Us Contact Us ... Links Tutorials Index Submit Tutorial Request Tutorial Organic Chemistry Index Important Tables Reactions Practice Tests Index Submit Practice Tests Request Practice Tests Online Quizzes Index Chemistry Olympiad Test Questions Submit Quizzes Request Quizzes Reference Tools Constants Formulas Glossary Periodic Table ... Thermodynamic Data Atoms: By Takalah Topics Covered Law of Multiple Proportions Dalton's Atomic Theory Intro to Atomic Structure Molecules and Ions ... Compound Naming This section introduces some basic concepts of chemistry. Law of Multiple Proportions The Law of Multiple Proportions simply states: When two elements form a series of compounds, the ratios of the masses of the second element that combine with 1 gram of the first element can always be reduced to small whole numbers. For those of you who are lost, it just means that only multiples of an amount of one element can react with a constant amount of another in a two element compound. For example, here is a table comparing three compounds of nitrogen and oxygen. Compound Amount of Nitrogen that reacts with 1 gram of oxygen Compound A 1.750 g

35. Learn Chemistry - Chemistry Glossary Dictionary : K-L - Kelvin Temperature Scale Lattice, a threedimensional system of points designating the positions ofthe centers of the components of a solid (atoms, ions, or molecules). http://www.learnchem.net/glossary/k.shtml

Main AP Chemistry News About Us Contact Us ... Links Tutorials Index Submit Tutorial Request Tutorial Organic Chemistry Index Important Tables Reactions Practice Tests Index Submit Practice Tests Request Practice Tests Online Quizzes Index Chemistry Olympiad Test Questions Submit Quizzes Request Quizzes Reference Tools Constants Formulas Glossary Periodic Table ... Thermodynamic Data Glossary: Kelvin Temperature Scale An absolute temperature scale with K at absolute zero and 273 K at the freezing point of water Kinetic Energy The energy of a mass resulting from its motion An object of mass m moving with a velocity v has kinetic energy / mv Kinetic molecular theory a model that assumes that an ideal gas is composed of tiny particles (molecules) in constant motion Lanthanides a group of fourteen elements following lanthanurn in the periodic table, in which the 4f orbitals are being filled Lanthanide Contraction The gradual decrease in atomic size of the inner transition elements following lanthanum in the periodic table f block Latent Image The invisible pattern formed on a photographic film by exposure to light Lattice a three-dimensional system of points designating the positions of the centers of the components of a solid (atoms, ions, or molecules)

36. The Educational Encyclopedia, Chemistry structure, atoms, ions, protons, isotopes. Atomic structure table of contents. Atomictheory of matter atomic structure, doc file. atoms and molecules the neutron http://users.telenet.be/educypedia/education/chemistrymol.htm

Science Animals Biology Botany Bouw ... Resources Chemistry Acids and bases Atoms and molecules Biochemistry Crystals Distillation Electro chemistry ... Spectroscopy Atomic structures Atoombouw en periodiek systeem in Dutch Atomen moleculen en stoffen in Dutch Atomic orbital theory Atomic structure Atomic structure Atomic structure timeline ... Atomic theory and bonding an atom consists of a small, dense nucleus containing all of its protons and neutrons, surrounded by electrons that fill the remaining volume of the atom, pdf file Atomic theory, elements, atoms and molecule Atomic and molecular structure: bonding pdf file Atomic structure atomic structure, atoms, ions, protons, isotopes Atomic structure table of contents Atomic theory of matter atomic structure, doc file Atoms and molecules the neutron is located in the atomic nucleus (except in Hydrogen). The neutron has no charge, and a mass of slightly over 1 amu. Some scientists propose the neutron is made up of a proton and electron like particle. The electron is a very small particle located outside the nucleus Atoms and molecules Chemical bonding Chemische bindingen in Dutch How do different sized atoms pack?

37. Cookies Required Theory of electron scattering by atoms, ions and molecules. PG BurkeDepartment of Applied Mathematics and Theoretical Physics, The http://link.aip.org/link/?APC/543/155/1&agg=aipArtMkt

38. Properties Of Solids a unit cell. The unit cell consists of a set of points that mark outthe positions of atoms, ions or molecules. The locations of http://scidiv.bcc.ctc.edu/wv/08/0008-0014-solids.html

Properties of solids Objectives name two types of solids give examples of crystalline and amorphous solids name the three types of cubic unit cells explain what a unit cell is and tell how many atoms are in a unit cell Types of solids Crystalline solids have atoms, molecules or ions arranged in a regular pattern. Sodium chloride is an example of a crystalline solid. These solids have a fundamental building block called a unit cell. The unit cell consists of a set of points that mark out the positions of atoms, ions or molecules. The locations of these points can generate a complete crystal when stacked or repeated in three dimensions. Amorphous solids have no regular pattern for molecule, atom or ion locations. Glass and tar are examples of amorphous solids. These types of matrials have NO simple repeated unit cell. The structure is more complicated because they lack the repetitive units. Examples of unit cells Cubic unit cells: Simple cubic, body centered cubic, face entered cubic

39. Electronegativity converting the atoms into ions (Na + ) and (Cl chloride ion is, in turn, held by 6sodium ions. Result a crystal lattice (not molecules) of common table salt http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/E/Electronegativity.html

Index to this page Ionic Bond Covalent Bond Polar Covalent Bond Electronegativity The affinity for electrons. The atoms of the various elements differ in their affinity for electrons. This image distorts the conventional periodic table of the elements so that the greater the electronegativity of an atom, the higher its position in the table. Although fluorine (F) is the most electronegative element, it is the electronegativity of runner-up oxygen (O) that is exploited by life. The shuttling of electrons between carbon (C) and oxygen (O) atoms powers life. Moving electrons against the gradient (O to C) - as occurs in photosynthesis - requires energy (and stores it). Moving electrons down the gradient (C to O) - as occurs in cellular respiration - releases energy. The relative electronegativity of two interacting atoms also plays a major part in determining what kind of chemical bond forms between them. Example 1 : Sodium (Na) and Chlorine (Cl) = Ionic Bond There is a large difference in electronegativity, so the chlorine atom takes an electron from the sodium atom converting the atoms into ions (Na ) and (Cl These are held together by their opposite electrical charge forming ionic bonds Each sodium ion is held by 6 chloride ions while each chloride ion is, in turn, held by 6 sodium ions.

40. Atoms, Molecules & Ions Name_ atoms, molecules ions. DIRECTionsCircle the answer that best completes each statement. http://users.rcn.com/fvirzi/chtest1.shtml

DIRECTIONS: Circle the answer that best completes each statement. 1. The elements whose symbols are P, C, and N are (a) potassium, cadmium, and nickel. (b) potassium, carbon, and nitrogen. (c) phosphorus, calcium, and neon. (d) phosphorus, carbon, and nitrogen. a b c d 2. The elements whose symbols are Mg, Ba, and Pt are (a) manganese, barium, and plutonium. (b) mercury, beryllium, and polonium. (c) magnesium, barium, and platinum. (d) mendelevium, bromine, and protactinium. a b c d 3. The symbols of bromine, oxygen, and sulfur are (a) Br, O, and S. (b) Br, Ox, and Sr. (c) B, O, and S. (d) B, Ox, and Sr. a b c d 4. H SO O . (c) The formula of hypochlorous acid is HClO. (d) The formula of phosphoric acid is H PO Co and the cation is either Fe or Fe can have the formulae (a) O Fe or Fe O (b) FeO or FeO (c) Fe O or Fe O (d) Fe O or FeO a b c d 10. The formulae of compounds which contain no other ions other than K , Sr , Br or O can include (a) SrBr (b) KBr (c) SrO (d) KO O and H O (b) Al (c) Li (d) S , SO , and CO are: (a) nitrite, sulfate, and carbonate (b) nitrate, sulfoxylate, and carboxide (c) nitrohydride, sulfotrioxylate, and oxocarbonium (d) ammonium, sulfite, and carbonate a b c d 18. Yttrium-90 is a radionuclide which is being studied for use in the treatment of cancer. Which of the following describes the

A  B  C  D  E  F  G  H  I  J  K  L  M  N  O  P  Q  R  S  T  U  V  W  X  Y  Z

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