Chapter 2 Flashcards
anion
a negatively charged ion
aqueous solution
a solution in which water is the solvent
atom
the smallest unit of an element that retains the chemical nature of the element. a neutral, spherical entity composed of a positively charged central nucleus surrounded by one or more negatively charged electron
atomic mass
the average of the masses of the naturally occurring isotopes of an element weighted according to their abundances
atomic mass unit
a mass exactly equal the mass of a carbon-12 atom
atomic number (Z)
the unique number of protons in the nucleus of each atom of an element (equal to the number of electrons in the neutral atom). an integer that expresses the positive charge of a nucleus or subatomic particle in multiples of the electronic charge
atomic symbol
a one- or two-letter abbreviation for the English, Latin, or Greek name of an element
atomic symbol
a one- or two-letter abbreviation for the English, Latin, or Greek name of an element
binary covalent compound
a compound that consists of atoms of two elements, typically nonmetals, in which bonding occurs primarily through electron sharing
binary ionic compound
a compound that consists of the oppositely charged ions of two elements
cathode ray
the ray of light emitted by the cathode (negative electrode) in a gas discharge tube; travels in a straight line, unless deflected by magnetic or electric fields
cation
a positively charged ion
chemical bond
the force that holds two atoms together in a molecule (or formula unit
chemical bond
the force that holds two atoms together in a molecule (or formula unit
chemical formula
a notation of atomic symbols and numerical subscripts that shows the type and number of each atom in a molecule or formula unit of a substance
chromatography
separation technique in which a mixture is dissolved in a fluid (gas or liquid) and the components are separated through differences in adsorption to (or solubility in) a solid surface (or viscous liquid)
chromatography
separation technique in which a mixture is dissolved in a fluid (gas or liquid) and the components are separated through differences in adsorption to (or solubility in) a solid surface (or viscous liquid)
compound
a substance composed of two or more elements that are chemically combined in fixed proportions
covalent bond
a type of bond in which atoms are bonded through the sharing of electrons; the mutual attraction of the nuclei and an electron pair that holds atoms together in a molecule
covalent bond
a type of bond in which atoms are bonded through the sharing of electrons; the mutual attraction of the nuclei and an electron pair that holds atoms together in a molecule
covalent bond
a type of bond in which atoms are bonded through the sharing of electrons; the mutual attraction of the nuclei and an electron pair that holds atoms together in a molecule
covalent compound
a compound that consists of atoms bonded together by shared electron pairs
crystallization
a technique used to separate and purify the components of a mixture through differences in solubility, resulting in a component coming out of solution as crystals
dalton (Da)
a unit of mass identical to atomic mass unit (amu)
dalton (Da)
a unit of mass identical to atomic mass unit (amu)
distillation
a separation technique in which a more volatile component of a mixture vaporizes and condenses separately from the less volatile components
electron (e-)
a subatomic particle that possesses a unit negative charge (− 1.60218 × 10−19 C) and occupies the space around the atomic nucleus
electron (e-)
a subatomic particle that possesses a unit negative charge (− 1.60218 × 10−19 C) and occupies the space around the atomic nucleus
element
the simplest type of substance with unique physical and chemical properties. an element consists of only one kind of atom, so it cannot be broken down into simpler substances
filtration
a method of separating the components of a mixture on the basis of differences in particle size
formula mass
the sum (in amu) of the atomic masses of a formula unit of a (usually ionic) compound
formula unit
the chemical unit of a compound that contains the relative numbers of the types of atoms or ions expressed in the chemical formula
fraction by mass
the portion of a compound’s mass contributed by an element; the mass of an element in a compound divided by the mass of the compound
group
a vertical column in the periodic table; elements in a group usually have the same outer electron configuration and, thus, similar chemical behavior
heterogeneous mixture
a mixture that has one or more visible boundaries among its components
homogeneous mixture
a mixture that has no visible boundaries among its components
hydrate
a compound in which a specific number of water molecules are associated with each formula unit
ion
a charged particle that forms from an atom (or covalently bonded group of atoms) when it gains or loses one or more electrons
ionic compound
a compound that consists of oppositely charged ions
isotopes
atoms of a given atomic number (that is, of a specific element) that have different numbers of neutrons and therefore different mass numbers
isotopic mass
the mass (in amu) of an isotope relative to the mass of carbon-12
law of definite (or constant) composition
a mass law stating that, no matter what its source, a particular compound is composed of the same elements in the same parts (fractions) by mass
law of mass conservation
a mass law stating that the total mass of substances does not change during a chemical reaction
law of multiple proportions
a mass law stating that, if elements A and B react to form two or more compounds, the different masses of B that combine with a fixed mass of A can be expressed as a ratio of small whole numbers
mass number (A)
the total number of protons and neutrons in the nucleus of an atom
mass spectrometry
an instrumental method for measuring the relative masses of particles in a sample by creating charged particles and separating them according to their mass/charge ratios
metal
a substance or mixture that is relatively shiny and malleable and is a good conductor of heat and electricity. In reactions, metals tend to transfer electrons to nonmetals and form ionic compounds
metalloid (semimetal)
an element with properties between those of metals and nonmetals
mixture
two or more elements and/or compounds that are physically intermingled but not chemically combined
molecular mass
the sum (in amu) of the atomic masses of the elements in a molecule (or formula unit) of a compound
molecule
a structure consisting of two or more atoms that are bound chemically and behave as an independent unit
molecule
a structure consisting of two or more atoms that are bound chemically and behave as an independent unit
monatomic ion
an ion derived from a single atom
neutron (n0)
an uncharged subatomic particle found in the nucleus, with a mass slightly greater than that of a proton.
nonmetal
an element that lacks metallic properties. in reactions, nonmetals tend to share electrons with each other to form covalent compounds or accept electrons from metals to form ionic compounds
nucleus
the tiny, central region of the atom that contains all the positive charge and essentially all the mass
oxoanion
an anion in which an element, usually a nonmetal, is bonded to one or more oxygen atoms
percent by mass (mass percent)
the fraction by mass expressed as a percentage
period
a horizontal row of the periodic table
periodic table of the elements
a table in which the elements are arranged by atomic number into columns (groups) and rows (periods)
periodic table of the elements
a table in which the elements are arranged by atomic number into columns (groups) and rows (periods)
polyatomic ion
an ion in which two or more atoms are bonded covalently
proton (p+)
a subatomic particle found in the nucleus that has a unit positive charge (1.60218 × 10−19 C)
substance
a type of matter, either an element or a compound, that has a fixed composition
volatility
the tendency of a substance to become a gas
what evidence led to the development of Dalton’s atomic theory?
mass conservation
definite composition
multiple proportions
what are the postulates to Dalton’s atomic theory?
- all matter consists of atoms
- atoms of one element can’t be converted to be atoms of another element
- atoms of an element are identical in mass and other properties
- compounds result from the chemical combination of a specific ratio of atoms of different elements
group 1A
the alkali metals (except H)
group 2A
the alkaline earth metals
group 6A
the oxygen group (chalcogens)
group 7A
the halogens
group 8A
the noble gases
Millikan
by balancing the upward electrical force acting on a charged oil droplet with the downward gravitational force, he could calculate the charge on the droplet (the charge of a single electron)
Thomson
model of the atom was a sphere of diffusely spread, positively charged matter in which tiny electrons were embedded (plum pudding model)
Rutherford
discovered that most of the mass in an atom is concentrated in the nucleus and that the positive charge in a nucleus was due to the proton
