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40 Cards in this Set
- Front
- Back
matter
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anything that takes up space and has mass
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element
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substance that cannot be broken down to other substances by chemical reactions
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compound
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substance consisting of two or more different elements combined in a fixed ratio
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essential elements
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20 to 25% of the 92 elements essential to healthy life
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trace elements
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required by an organism in only minute quantities
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atom
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smallest unit of matter that still retains the properties of an element
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neutrons
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neutral charge, in the nucleus, mass of 1
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protons
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positive charge, in the nucleus, mass of 1
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electrons
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negative charge, in the electron cloud, mass of 0
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atomic nucleus
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center of atom, contains protons and neutrons
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atomic number
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number of protons
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mass number or atomic mass
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neutrons + protons
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isotopes
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same atom different number of neutrons
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radioactive isotopes
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nucleus decays spontaneously, or the nucleus has the tendency to lose particles, unstable
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energy
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capacity to change
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potential energy
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energy matter possesses because of location and structure, most common in the form of chemical energy
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electron shells
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levels of energy at different distances from the nucleus
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valence electrons
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outer electrons
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valence shell
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outermost shell
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orbital
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dimension in space where an electron can be found 90% of the time
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chemical bonds
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attractions that hold atoms close together
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covalent bond
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sharing a pair of valence electrons by two atoms
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molecule
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two or more atoms of the same type held together by covalent bonds
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single or double bonds
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sharing one or two electrons at a time
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valence
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bonding capacity, usually equals the number of unpaired electrons required to complete the atom’s outermost shell
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electronegativity
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attraction of a particular atom for the electrons of a covalent bond
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nonpolar covalent bond
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electrons are shared equally
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polar covalent bond
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electrons are not shared equally
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ion
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charged atom or molecule (not neutral)
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cation
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positively charged ion
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anion
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negatively charged ion
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ionic bond
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cations and anions are attracted to each other
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ionic compounds or salts
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compounds formed by ionic bonds
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hydrogen bond
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when partially positively charged hydrogen is bonded to an electronegative atom the hydrogen is attracted to a different electronegative atom nearby
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van der waals interactions
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this can occur in both polar and nonpolar bonds, atoms are not arranged symmetrically so there are regions of positive or negative charge that enable all atoms and molecules to stick to one another
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chemical reactions
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making and breaking of chemical bonds that lead to changes in the composition of matter
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reactants
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starting materials of a chemical reactions
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products
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what you get out of a chemical reaction
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chemical equilibrium
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forward and reverse reactions occur at the same rate, there can be change but ultimately they are balanced
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strongest bonds
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covalent bonds and iconic bonds
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