exam_2_chapters_2,3,5,6,7,8,9,10

Exam_2_chapters_2,3, - CHAPTER 2 The Chemical Basis Of Life ELEMENTS AND ATOMS Elements substances that cannot be broken down into simpler

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CHAPTER 2: The Chemical Basis Of Life ELEMENTS AND ATOMS Elements- substances that cannot be broken down into simpler substances by ordinary chemical reactions --96% of the mass of most organisms: Carbon, Hydrogen, Oxygen, and Nitrogen --Other 4%-calcium, phosphorus, potassium, sulfur, sodium, magnesium, chlorine, iron, (trace amounts of: Iodine, manganese, copper, zinc, cobalt, fluorine, molybdenum, selenium, boron, silicon, etc) Atom- defined as the smallest portion of an element that retains its chemical properties Matter- Anything that takes up space and has a mass. --Atoms are comprised of : Protons(+), Neutrons(no charge), and Electrons (-). --Atomic nucleus is comprised of neutron and protons. Atomic Number- amount of proton is an atoms nucleus. Atomic Mass- amount of proton and neutrons in an atom, how much matter is in an atom(mass). AMU- approximate mass of one proton or neutron Isotopes- atoms with the same # of protons but with a different # of neutrons. Elements with different weights. Radioisotope- radioactive unstable isotope that emits radiation as it decays. ELECTRONS Orbital- 3-D space that an electron moves through. (maximum of 2) --Electrons in orbitals with similar energy levels are said to be at the same Principle Energy Level (Electron Shell) Valence Electrons- The outer most electrons and the most energetic (compose valence shell) CHEMICAL REACTIONS --Chemical behavior of an atom is determined by the number and arrangement of its valence electrons. Chemical Compound- consists of atoms of two or more different elements combined in a fixed ratio. Molecule- two or more atoms joined very strongly to form a stable particle. Empirical formula- describes the chemical composition of a molecule in its smallest whole number ratio in its subscripts. Molecular formula- subscript indicate the actual number of each type of atom in a molecule.
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Structural formula- shows the number and arrangement of atoms in a molecule. (certain complex organic molecules commonly share similar molecular formulas.) Molecular mass – the sum of the atomic masses of the components in a molecule. Mole= the weight in grams of a molecule(derived from its molecular mass.) Avogadro’s number= 6.02 x 10^23 molecules/moles -Chemical equation describes a reaction (reactants on the left, products on the right) Dynamic equilibrium – point in a reaction where the rates of the forward reaction equals the rate of the reverse. CHEMICAL BONDS Chemical Bonds- forces of attraction that hold atoms together. (covalent or ionic) Bond energy- the energy necessary to break a chemical bond. Covalent bond- involves the sharing of electrons between atoms that result in a complete valence shell. (represented by a Lewis structure)
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This note was uploaded on 01/18/2012 for the course BIO 101 taught by Professor Martin during the Fall '08 term at Rutgers.

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Exam_2_chapters_2,3, - CHAPTER 2 The Chemical Basis Of Life ELEMENTS AND ATOMS Elements substances that cannot be broken down into simpler

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