Chapter 2: Atoms, Ions, & Molecules Flashcards
Radioactivity
The spontaneous emission of high-energy radiation & particles by materials
Electron
A subatomic particle that has a negative charge & little mass
Beta particle
A radioactive emission equivalent to a high-energy electron
Alpha particle
A radioactive emission with a charge of 2+ and a mass equivalent to that of a helium nucleus
Nucleus
The positively charged Center of an atom that contains nearly all the atom’s mass
Protons
A positively charged subatomic particle present in the nucleus of an atom
Neutron
An electrically neutral (uncharged) subatomic particle found in the nucleus of an atom
Unified atomic mass units (u)
Unit used to express the relative masses of atoms & subatomic particles; it is exactly 1/2 the mass of one atom of carbon with 6 protons & 6 neutrons in its nucleus
Dalton (Da)
A unit of mass identical to 1 unified atomic mass unit(u); thus 1Da=1u
Isotopes
Atoms of the same element that contain different numbers of neutrons
Atomic number (Z)
The number of protons in the nucleus of an atom
Nucleons
Either a proton or a neutron in a nucleus
Mass number (A)
The number of nucleons in an atom
Nuclide
At atom with particular numbers of neutrons & protons in its nucleus
Average atomic mass
The weighted average of the masses of all the isotopes of the element
Natural abundances
The proportion of an isotope, usually expressed in percent, relative to all the isotopes of that element in a natural sample
Periods
The 7 Horizontal row in the periodic table
Groups or families
The 18 columns - all the elements in the same column of the periodic table
Metals
The elements on the left side of the periodic table that are typically shiny solids that conduct heat and electricity well and are malleable and ductile
Nonmetals
The elements with properties opposite of metals, including poor conductivity of heat & electricity
Metalloids or semi metals
The elements along the border of metals and nonmetals; they have some metallic and some nonmetallic properties
Main group elements
The elements in groups 1-2 and 13-18 of the periodic table
Transition metals
The elements in groups 3-12
Halogens
The elements in group 17 of the periodic table (salt formers)
Alkali metals
The elements in group 1 of the periodic table
Alkaline earth metals
The elements in group 2 of the periodic table
Noble gases
The elements in group 18 of the periodic table
Law of multiple proportions
The principle that, when 2 masses of one element react with a given mass of another element to form 2 different compounds, the 2 masses of the first element have a ratio of 2 small whole numbers
Molecular compounds
A compound composed of molecules that contain the atoms of 2 or more elements covalently bonded together
Covalent bonds
A bond between 2 atoms created by sharing one or more pairs of electrons
Molecular formulas
A notation showing the number & type of atoms present in one molecules of a molecular compound
Ionic compounds
A compound composed of positively & negatively charged ions held together by electrostatic attraction
Empirical formulas
A formula showing the smallest whole-number ratio of the elements in a compound
Formula unit
The smallest electrically neutral unit of an ionic compound
Chemical nomenclature
The rules that are followed in naming substances
Organic compounds
Compound composed of molecules containing carbon combined with hydrogen and other elements, such as nitrogen, oxygen, phosphorus, and sulfur
Polyatomic ions
A charged group of 2 or more atoms joined by covalent bonds
Heteroatoms
An atom of element other than carbon & hydrogen within a molecule of an organic compound
Organic chemistry
The study of organic compounds (oxygen, nitrogen, sulfur, phosphorus, and the halogens)
Hydrocarbons
An organic compound whose molecules are composed only of carbon and hydrogen atoms
Alkenes
A hydrocarbon containing one or more carbon-carbon double bonds
Alkanes
A hydrocarbon in which all the bonds are single bonds
Alkynes
A hydrocarbon containing one or more carbon-carbon triple bonds
Adding OH
Ends in -ol (methanol)
Alcohols
An organic compound containing the OH functional group
Functional group
A group of atoms in the molecular structure of an organic compound that imparts characteristic chemical & physical properties
Quarks
Elementary particles that combine to form neutrons and protons
Nucleosynthesis
The natural formation of nuclei because of fusion and other nuclear processes
Neutron capture
The absorption of a neutron by a nucleus
Beta decay
A spontaneous process by which a neutron in a radioactive nuclide is transformed into a proton and emits a high-energy electron
