| Terms |
Definitions |
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absolute zero
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0 K or -273.15 degrees celsius, theoretical lowest temperature
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molecular formula
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shows the exact number of atoms of each element in the smallest unit of a substance
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ion
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charged particle formed when an atom or olecule gains or loses electrons
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quantitative
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comprising of numbers obtained from various measurements of the system
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alkaline earth metals
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group 2A elements
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molar mass
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the mass of 1 mole of particles
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mixture
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a combination of two or more substances in which the substances retain their distinct identities
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atom
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the basic unit of an element that can enter into chemilcal combination
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cation
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an ion with a positive charge
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groups/families
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elements in a vertical column which also have similar chemical properties
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radiation
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the emission and transmission of energy through space in the form of waves
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molecular mass
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the sum of the atomic masses in the molecule, can be used the same way as the atomic mass
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halogens
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elements in 7A
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periods
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horizontal rows on the periodic table
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noble gasses
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elements in 8A
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atomic mass
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the mass of the atom in atomic mass units (also grams)
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mole (mol)
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the amount of a substance that contains as many particles as there are atoms in exactly 12 grams of the carbon 12 isotope, simply a convienient way of counting an extremely large number of particles
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mass number
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the total number of neutrons and protons present in the nucleus
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homogenous mixture
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the composition of the mixture is the same throughout
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chemical formulas
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expresses the composition of molecules and ionic compounds in terms of chemical symbols
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isotopes
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atoms that have the same atomic number but different mass numbers
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element
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a substance that cannot be separated into simpler substances by chemical means
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periodic table
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a chart in which elements having similar chemical and physical properties are grouped together
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accuracy
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how close a measurement is to the true value of the quantity that was measured
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chemical property
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in order to observe this property we must carry out a chemical change
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precision
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how closely two or more measurements of the same quantity agree with each other
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heterogenous mixture
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the composition is not uniform
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matter
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anything that occupies space and has mass
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kelvin
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the SI base of temperature
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radioactivity
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spontaneous emission of particles/radiation
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law of conservation of mass
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matter is neither created or destroyed
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alkali metals
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group 1A elements
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qualitative
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consisting of general observations about the system
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significant figures
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the meaningful digits in a measured or calculated quantity
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empirical formula
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tells us which elements are present and the simplest whole number ratio of their atoms, but not necessarily the actual number of atoms in a given molecule
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avogadros number
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1 mole = 6.022 x 10^23 particles
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molecule
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substance formed when an atom or molecule gains or loses electrons
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anion
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an ion with a negative charge
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compound
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a substance composed of atoms of two or more elements chemically united in fixed proportions
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atomic number
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the number of protons in the nucleus of each atom of an element
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law of definite proportions
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different samples of the same compound always contain its constituent elements in the same proportion by mass
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physical property
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can be measured and observed without changing the composition or identity of a substance
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Chemistry
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the study of matter and the changes it undergoes
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