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59 Cards in this Set
- Front
- Back
atoms
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subatomic particles that are the fundamental building blocks of ordinary matter
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molecules
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atoms bonded together in specific geometrical arrangements
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hypothesis
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tentative interpretation of explanation of observations
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scientific law
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brief statement that summarizes past observations and predicts future ones
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scientific theory
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a model for the way nature is and tries to explain what nature does and why
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pure substance
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made up of only one component and its composition is the same throughout
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mixture
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composed of two or more components in proportions that can vary from one sample to another
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compound
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a substance composed of two or more elements
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heterogeneous mixture
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composition varies from one region of the mixture to another (wet sand)
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homogeneous mixture
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same composition throughout (sweetened tea)
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decanting
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separating by slowly pouring off (water and sand)
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distillation
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slowly boiling off more volatile (easily evaporated) liquid
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units
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standard quantities used to specify measurements
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International System of Units (SI)
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based on the metric system
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SI base units:
Length, Mass, Time, Temp, Amount of substance, electric current, luminous intensity |
meter(m), kilogram(kg), second(s), kelvin(K), mole(mol), ampere(A), candela(cd)
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derived unit
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a combination of other units (m/s)
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intensive property
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one that is independent of the amount of a substance (density)
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extensive property
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one that depends on the amount of a substance (mass)
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significant figures
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non-place holding digits
0.0032=2 sig 0.00006=1 sig 45.000=5 sig 1200=ambiguous |
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exact numbers
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have no uncertainty, therefore do not limit the number of sig figs in any calculation
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accuracy
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how close the measured value is to the actual value
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precision
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how close a series of measurements are to one another or how reproducible they are
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law of definite proportions
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all samples of a given compound, regardless of their source or how they were prepared, have the same proportions of their constituent elements
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law of multiple proportions
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when two elements (A and B) form two different compounds, the masses of element B combine with 1g of element A can be expressed as a ratio of small whole numbers
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electron
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negatively charged, low mass particle.
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radioactivity
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the emission of small energetic particles from the core of certain unstable atoms
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nuclear theory
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most of the atoms mass and all of its positive charge are contained in the nucleus
most of the volume of the atom is empty space, throughout which tiny electrons are dispersed. |
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neutron
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similar in mass to a proton, neutral charge (hydrogen contains no neutron)
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atomic mass unit (amu)
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1/12 the mass of a carbon atom containing six protons and six neutrons, the mass of a proton or a neutron is approximately 1amu.
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atomic number
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given by the symbol, Z. Is the number of protons in the atoms nucleus.
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isotopes
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atoms with the same number of protons but differing numbers of neutrons.
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natural abundance
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the natural amount of an elements isotope.
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ion
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an atom that has gained or lost electrons, causing it to become a charged particle
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cation
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positively charged ion
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anion
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negatively charged ion. named ny adding "ide" to the end of the elements name
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metals
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lie in groups 1A,2A, 2-12, and to the left of the line. metals for cations. conductors of heat and electricity. malleable. ductile.
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non-metals
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C, N+, O++, F+++, group 8, H. appear in all three states, poor conductors. not ductile or malleable. solids are brittle.
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metalloids
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B, Si, Ge, As, Sb, Te, Po. B then right 1-down 1, zig zag to Po. Exhibit mixed properties, semiconductors.
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semiconductor
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highly temperature dependent, electrically conductive.
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transition metals
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rectangle in the middle. properties tend to be less predictable
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family
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horizontal rows
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groups
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vertical columns
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noble gases
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8A, mostly unreactive, very stable.
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alkali metals
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group 1A, reactive metals, =
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alkaline earth metals
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group 2A, fairly reactive metals, not quite as reactive as 1A
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halogens
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group 7A, very reactive nonmetals.
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atomic mass
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beneath each element on the periodic table. represents the average mass of the isotopes that compose that element , weighted according to the natural abundance of each isotope.
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mass spectrometry
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technique that separates particles according to their mass.
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mol
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6.022*10^23 atoms per mol (Avogadro's number)
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molar mass
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the mass if one mol of atoms of an element
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giga
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10^9
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mega
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10^6
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kilo
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10^3
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deci
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10^-1
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centi
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10^-2
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milli
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10^-3
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micro
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10^-6
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nano
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10^-9
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diatomic elemets
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O, H, N, F, Cl, I, Br
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