de Broglie used the term matter waves to describe the wave-like properties of matter. With the regards to the atom‚ de Broglie concluded that an electron orbiting a nucleus could be thought of as a wave possessing a characteristic wavelength. Example. Calculate the wavelengths of the following objects. (a) a baseball weighing 142 g thrown at 142 km/h. (b) a helium atom moving at a speed of 8.5 x 105 m/s. The importance of the above example...... CH 5-2-3 The
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NUCLEUS The positively charged dense central part of an atom. In Biology the term first introduced by Miescher‚ employed to describe a structure round in the cells of with the tissues of animals and plants are composed. In general it is a viscous spherical body containing a structure known as the plasmosome or nucleolus and a tangle of material chromatin characterized by a special affinity for basic dyes‚ usually spherical mass of protoplasm found in the most living cells that directs the activities
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fundamental principles Experimental Work * Atoms of different elements have different properties * Law of definite proportion and multiple compositions: atoms of 2 or more elements can combine in a fixed ratio to form new substances depending on their combining capacities (eg. H2O vs H2O2) * Law of conservation of mass: atoms cannot be created or destroyed during a chemical reaction Conclusions * All matter is composed of atoms * Atoms are the smallest pieces of matter and cannot
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Lab 1: Synthesis of Aspirin Introduction: The purpose of this lab was to demonstrate the ability to easily alter the molecular structure of a compound to greatly increase its utility. In this case‚ an acetyl group was added to salicylic acid‚ a naturally occurring compound with significant pharmaceutical value. Without the addition of the acetyl group‚ salicylic acid is an irritant to the gastro-intestinal (GI) tract. Once the acetyl group is added via a simple reaction‚ acetylsalicylic
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formed between a metal and a non-metal‚ Covalent between two non-metals and Metallic between two metals. Ionic Bonding; Ionic bonds tend to form between metals whose atoms need to “loose” electrons to gain the nearest noble gas configuration and non-metals that need to gain electrons. These electrons are transferred from one atom to another. This gives one ion a positive charge and the other a negative one. The Opposite charges in the ion hold them together in a regular three dimensional lattice
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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. [pic] If the atoms are
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iron (Fe) atom will react with two oxygen (O) atoms to yield 2 iron atoms and 3 oxygen atoms. (The subscript number‚ such as the two in O2 describe how many atoms of an element are in a molecule.) This unbalanced reaction can’t possibly represent a real reaction because it describes a reaction in which one Fe atom magically becomes two Fe atoms. Therefore‚ we must balance the equation by placing coefficients before the various molecules and atoms to ensure that the number of atoms on the left
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in 181 by John Jakob Berzelius. The system is based on the law of definite proportions”‚ states that all samples of a given chemical compound have the same elemental composition. It is also a way of expressing information about the proportions of atoms that constitute a particular chemical compound‚ using a single line of chemical element symbols‚ numbers‚ and sometimes also other symbols‚ such as parentheses‚ dashes‚ brackets‚ and plus (+) and minus (−) signs. These are limited to a single typographic
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29) The structural formulas are given for these cis or trans alkenes. (a) trans-1‚2-dichloropropane (b) cis-2-pentene (c) cis-3-hexene (d) trans-2-hexene Write the structural formula for: (a) cis-1‚2-dichloropropene (b) trans-2-pentene (c) trans-3-hexene (d) cis-2-hexene 30) In each case‚ tell whether cis and trans exist. If they do‚ write the structural formulas for two isomers and label each cis or trans‚ (a) Br2CH2 : No (b) CH3CH2CH=CHCH2CH3: Yes (c) CH3CH=CHCH3:
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THE CHEMISTRY OF ORGANIC MOLECULES I. MACROMOLECULES-large molecules that are composed of smaller molecules and atoms that are bonded together. These are among the largest of all chemical molecules. A. Polymers-the largest of the macromolecules. These are composed of numerous‚ small identical subunits known as Monomers. There are 4 major polymers that are important for living organisms. These polymers are; carbohydrates‚ lipids‚ proteins and nucleic acids. B. Polymers
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