Chemistry Terms
63. chemical: a term used to descried a specific kind of atom or molecule
64. chemistry: the study of matter at the atomic level
65. atom: the smallest particle of an element that still has all the properties of that element
66. element: a pure substance made of only one kind of atom (approx. 92 natural elements)
67. molecule : molecules are made up of two or more atoms, the smallest amount of a compound that still
has all the properties of the compound
68. nucleus: the central part of an atom made up of protons and neutrons
69. proton: positively charged particle of the atom found in the nucleus
(each positively charged proton attracts 1 negatively charged electron)
70. neutron: particle of the atom with no charge found in the nucleus
71. electron: negatively charged particle of the atom found circling the nucleus (each negatively charged electron
is attracted by 1 positively charged proton)
72. electron cloud: is the area around the atom’s nucleus where the electrons are found (also called: orbit,
orbital, shell & energy level)
73. solid: the state of matter that has a definite shape and volume
74. liquid: the state of matter that does not have a definite shape but does have a definite volume
75. gas: the state of matter that does not have a definite shape or volume
76. interface: a boundary between two different substances
77. melting : when a solid changes into a liquid
78. freezing : when a liquid changes into a solid
79. evaporation: when a liquid changes into a gas
80. boiling: when a liquid quickly changes into a gas because it is heated
81. condensation: when a gas changes into a liquid due to a drop in temperature
82. solidification: when any other state of matter changes into a solid
83. liquefaction: when any other state of matter changes into a liquid
84. vaporization: when any other state of matter changes into a gas; (vapor is another word for gas)
85. sublimation: when a gas changes directly into a solid or when a solid changes directly into a gas (without
going into a liquid state)
86. physical property: any characteristic of a substance that can be observed using the senses
87. physical change: a change in the size, shape or state of matter, (the original substance remains the same)
88. chemical property: a characteristic of a substance that describes how it behaves in a chemical reaction.
89. chemical reaction (change): a change that results in a new chemical or chemicals (the original substance(s) is
changed into something new)
90. reactant: a chemical that is present when the chemical reaction begins
91. product: a new substance (chemical) present at the end of a chemical reaction
92. solution: formed when one substance is mixed completely with another
93. solute: the part of a solution that is dissolved (usually a solid)
94. solvent: the part of the solution that does the dissolving (larger amount/usually a liquid)
95. mixture: any solution that can be easily separated (by screen, filter, evaporation etc.)
96. compound: a substance made up of two or more different elements (water - H2O - is made of two different
elements: hydrogen and oxygen)
97. periodic table: a chart of all the known elements: it gives information about the atoms of the different
elements
98. chemical symbol: an abbreviation that represents each of the known elements on the periodic table and
is used in chemical formulas (C - carbon, Fe - iron)
99. chemical formula: a description of a compound using chemical symbols and numbers (water’s chemical formula
is H2O meaning 2 atoms of hydrogen and 1 atom of oxygen; glucose is C6H12O6)
100.
atomic number: the number of protons in an atom
101.
mass number (atomic mass) - total number of protons and neutrons in the nucleus of an atom