Science Chapter 13-14 Flashcards
The organized study of the composition and interactions of matter.
Chemistry
The foundation for the understanding of matter.
Atomic theory of matter
Who created the atomic theory of matter?
Dalton
Tiny particles that compose all matter.
Atoms
A substance composed of a single type of atom.
Element
A substance composed of atoms of two or more elements bonded together.
Compound
A substance that is composed of several pure substances that are physically mixed but not chemically united.
Mixture
A unique abbreviation given to each element.
Chemical symbol
Any of the smaller particles of matter of which atoms are composed.
Subatomic particles
The dense central core of an atom made of protons and neutrons.
Nucleus
Subatomic particle that carries a positive electrical charge and determines the identity of an atom.
Proton
The number of protons in the nucleus of an atom.
Atomic number
Subatomic particle that is electrically neutral with no electric charge.
Neutron
Any of a group of atoms that are the same element but have different numbers of neutrons.
Isotope
Any of the small particles that compose protons and neutrons.
Quarks
_____ quarks are needed to make a proton or a neutron.
Three
Subatomic particle that is found outside the nucleus and carries a negative electric charge equal in strength to a proton’s positive charge.
Electron
Any of the concentric layers surrounding the nucleus in which electrons can be found.
Electron shell
An atom normally has the ______ number of protons and electrons.
Same
An atom that has an electric charge because of losing or gaining electrons.
Ion
Positive ions are
Cations
Negative ions are
Anions
The total number of protons and neutrons in the nucleus of an atom or isotope.
Mass number
A unit used to measure the masses of atoms; equal to exactly 1/12 the mass of a carbon-12 atom.
Atomic mass unit
The mass of an atom in atomic mass units is approximately equal to the ________
Mass number
The average mass of all the natural isotopes of an element, calculated according to the isotopes’ relative abundances.
Average atomic mass
The theory stating that tiny particles like electrons do not absorb or release energy in a smooth flow.
Quantum theory
The most familiar model of the atom, which pictures the nucleus surrounded by electrons that move in circular orbits at specific energy levels.
Bohr model
An atomic model that describes the electrons as waves around the nucleus.
Wave-mechanical model
Electrons have characteristics of both ________ and ________.
particles, waves
The principle stating that it is impossible to measure both the position and velocity of an electron with certainty.
Heisenberg uncertainty principle
A model of the atom that interprets the mathematical equations of the wave-mechanical model representing the probability of finding an electron at a given point.
Electron-cloud model
The region within an atom in which electrons move.
Orbital
A set of numbers that mathematically represents the overall motion of an electron.
Quantum numbers
The principle stating that no two electrons in an atom can have the same four quantum numbers.
Pauli exclusion principle
The nuclei of most atoms are ______, but the nuclei of some isotopes are ______, capable of breaking up or otherwise changing into another type of atom.
stable, unstable
Particles or electromagnetic waves given off when an atomic nucleus breaks up or undergoes a change.
Nuclear radiation
Any substance that is unstable.
Radioactive
The breakup or change of an atomic nucleus from a higher energy state to a lower energy state, emitting radiation.
Radioactive decay
The length of time required for one-half of an original substance to decay into a new substance.
Half life
The half-life of radium-226 is _______ years.
1,600
Radioactive decay that occurs when an unstable atom ejects a clump of 2 protons and 2 neutrons.
Alpha decay
Radioactive decay that occurs when a neutron in an atom’s nucleus changes into a proton, emitting an electron.
Beta decay
Radioactive decay that occurs when an excited (unusually energetic) nucleus releases energy without a change in the number of protons or neutrons.
Gamma decay
Nuclear radiation that can harm living things by disrupting the chemical process within cells; includes alpha particles, beta particles, and gamma rays.
Ionizing radiation
The process whereby a heavy nucleus is split into several pieces by bombarding it with neutrons.
Nuclear fission
The situation in which free neutrons released by nuclear fission cause other atoms to undergo nuclear fission and release more neutrons.
Chain reaction
Chain reaction is known as a ______ effect.
Domino
The minimum amount of fissionable material that must be present for a chain reaction to occur.
Critical mass
A device that works by initiating an uncontrolled nuclear fission chain reaction.
Atomic bomb
A device that harnesses controlled fission to produce useful energy.
Nuclear reactor
A nuclear reactor that recycles spent nuclear fuel to produce more than it uses.
Breeder reactor
The process of combining two nuclei to form a heavier nucleus and thereby releasing energy
Nuclear fusion
A weapon that uses nuclear fusion to release a tremendous amount of energy.
Hydrogen bomb
Any of the electrons in the outer shell of an atom.
Valence electron
The rule stating that an atom tends to react in a way that fills its valence shell with eight electrons.
Octet rule
The law that states that elements show regular and repeating, or periodic, properties when they are arranged by their increasing atomic numbers.
Periodic law
A table of the elements arranged by atomic number and number of valence electrons.
Periodic table of the elements
A row of the periodic table.
Period
A column on the periodic table.
Group
Any of the elements in groups 1,2, and 13-18.
Main-group element
Any of the group of elements that are typically hard, dense, shiny solids; are good conductors of heat and electricity; and have high melting points.
Metal
Any of the group of elements that are typically poor conductors of electricity and heat.
Nonmetal
Any of the solid elements that have properties intermediate between metals and nonmetals.
Semimetal
Any element in group 1.
Alkali metal
The first most abundant element in the human body.
Oxygen
The second most abundant element in the human body.
Carbon
The third most abundant element in the human body.
Hydrogen
Any element in group 2.
Alkaline earth metal
Any element in groups 3-12.
Transition metals
Any of the metals that lie beneath the main body of the periodic table, between groups 3 and 4; the Lanthanoids and Actinoids.
Inner transition metal
Group 15 is referred to as the _______.
Pnictogens
Group 16 is called _______.
Chalcogens
Meaning “salt former” is any element in group 17.
Halogen
Any element in group 18.
Noble gas
a group of two or more atoms linked by chemical bonds to form distinct units
molecule
a _________ is a combination of chemical symbols and numbers showing the type and number of atoms in each compound
chemical formula
Oxygen and Hydrogen are _________
diatomic
C60 is named after __________
Buckminsterfullerene
the sum of the atomic masses of all the atoms in a molecule
molecular mass
substances composed of atoms of two or more elements bonded together
compounds
molecules that have the same molecular formula but different structural formulas
isomer
a substance that has the same physical properties throughout and consists of only one type of atom, one type of molecule, or one nonmolecular compound; all pure substances are either elements or compounds
pure substances
a substance that has the same physical properties throughout the substance
homogenous
three-dimensional representation of a molecule that shows its shape and the position of its atom
molecular model
a substance composed of several pure substances that are physically mixed but not chemically united.
mixture
a homogeneous mixture that exists because of attraction between atoms, molecules, or ions.
solution
a substance in a solution that is dissolved.
solute
a substance in a solution that does the dissolving.
solvent
The key difference between solutions and pure substances is that, like all mixtures, a solution is a ________ mixture, not a ________ combination.
physical, chemical
describes a mixture in which the molecules of the mixed substances are not completely mixed.
heterogenous
a mixture containing tiny suspended clumps or particles.
colloid
the appearance of a blue-tinged milky or cloudy effect within a colloid when a light shines through it.
tyndall effect
a heterogeneous mixture whose particles are large enough that they will settle.
suspension
an attractive force that links atoms to form molecules and compounds.
chemical bond
The most important factor affecting how chemical bonds form is the number of _______ in the valence shell of each atom involved.
electrons
a chemical bond resulting from the sharing of valence electrons between atoms.
covalent bond
Covalent bonds typically form between two ________.
nonmetals
a covalent bond involving an electron.
single bond
a covalent bond formed by the sharing of two pairs of electrons.
double bond
a covalent bond in which three pairs of electrons are shared.
triple bond
a diagram showing the locations of all the atoms and valence electrons in a molecule or ion.
lewis structure
