particles called atom. He tried to break down matters into smallest particles. His model was that the matter would stop splitting in halves when it reaches its smallest matter. He called that an atom. * John Dalton In 1803‚ John Dalton proposed a theory. The theory had 4 parts into it. 1. Elements are made of identical atoms. 2. Atoms of different elements are physically different 3. Compounds are formed by a combination of two or more different kinds of atoms. 4. A chemical
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change. -snow melting and freezing into ice -fuel being changed into gas for cars -ponds freezing over to have a layer of ice Page 2 : E:\CC_Software\Workbench\CC-MW-CD\part2\phasechange\page2.cml 1. Describe the motion of atoms and molecules in a gas. the atoms and molecules bounce off one another each time they come in contact with eachother. they never bond‚ but reflect off of eachother and spread around. 2. How are the behavior and arrangements of gas molecules similar to and different
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The Periodic Properties of Atoms The Periodic Table: In the 1870’s‚ the Russian chemist Mendeleev developed the periodic table‚ based upon the relationship between the atomic weights of the elements and their chemical properties. As one ascends from lightest to heaviest elements‚ there is a periodic recurrence of chemical properties. For example‚ the elements with atomic numbers 2‚ 10‚ 18‚ 36‚ 54‚ and 86 all are chemically inert (the noble gases)‚ while those with atomic numbers one greater 3‚ 11
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Please silence and put away all cell phones and pagers! Part I. This section is multiple-choice. Fill in the letter corresponding to the best answer on your Scantron form #882. 1. The __________ and __________ contribute most to the mass of an atom‚ while the _____________ determines the atom’s chemical behavior. A. B. C. D. E. proton‚ neutron‚ electron proton‚ electron‚ neutron neutron‚ electron‚ proton proton‚ photon‚ neutron none of the above 2. The symbol 63 Cu represents an isotope of
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Atoms and Molecules Basic units of EVERYTHING! Which of these is true? 1. “Atom” and “molecule” mean the same thing. 2. Atoms are made of molecules. 3. Molecules are made of atoms. What is the smallest structure in this list that can be seen with an ordinary desk microscope? 1. 2. 3. 4. Cells. Cell nucleus. Atoms. Chain molecules‚ such as proteins. Atoms In our model of scale‚ remember that the BB represented an atom. Electrons Hydrogen Helium Neutrons Protons As a class‚ identify
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The atom is a basic unit of matter that consists of a dense central nucleus surrounded by a cloud of negatively charged electrons. Atoms lack a well-defined outer boundary‚ so their dimensions are usually described in terms of an atomic radius. This is a measure of the distance out to which the electron cloud extends from the nucleus. However‚ this assumes the atom to exhibit a spherical shape‚ which is only obeyed for atoms in vacuum or free space. Atomic radii may be derived from the distances
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Atoms‚ Molecules and Elements Atoms‚ molecules and elements are the building blocks of everything we can see‚ hear‚ and touch. Though not visible to the naked eye‚ it is the combination of millions of these tiny substances that make us who and what we are today. Many elements make up the world around us‚ and each element reacts differently to its surroundings. The definition of reactivity as pertained to chemistry states‚ “The relative capacity of an atom‚ molecule‚ or radical to undergo a chemical
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Atoms‚ Molecules‚ and Elements CHM/110 William De Vorick June 30‚ 2014 Atoms‚ Molecules‚ and Elements 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
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NOT base your answer on tabulated values since exceptions may occur. | germanium smallest arsenic selenium bromine largest Feedback: Electronegativity is the ability of an atom in a molecule to attract electrons to itself. In general‚ electronegativity increases as the atomic radius decreases. Smaller atoms have higher electronegativities. Notice that all of these elements are in row 4. Across a row of the periodic table‚ atomic radius decreases with increasing atomic number. The
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Atoms Atom is the fundamental building block of all stuff‚ or what scientists like to call "matter". An individual atom is very small. In fact‚ the smallest type of atom‚ hydrogen‚ has a diameter of 10-8 cm. Every single object is composed of atoms. Our body is made up of many‚ many individual atoms. There are also many different types of atom. These different types are called elements. Examples of some elements are hydrogen‚ oxygen‚ and helium. Under normal conditions many atoms can stick together
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