Science 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 (proposed by Dalton)
tiny particles that compose all matter
atoms (“not cuttable”)
substances composed of a single type of atom
elements
composed of atoms of two or more elements bonded together
compounds
a unique abbreviation given to elements that is typically based on its common or Latin name
chemical symbol
atoms are composed of still smaller particles of matter called _______
subatomic particles
the dense central core of an atom
nucleus
part of an atom that carries a positive electric charge
proton
part of an atom that is neutral (no electric charge)
neutron
the number of protons in the nucleus
atomic number
atoms that are the same element but have different numbers of neutrons
isotopes
small particles that make up protons and neutrons
quarks
part of an atom that carries a negative electric charge
electron
concentric layers that surround the nucleus
electron shells
atom that has an electric charge because of losing or gaining electrons
ion
negative ions
anions
positive ions
cations
the total number of protons and neutrons in the nucleus
mass number
the average mass of all the natural isotopes of an element
average atomic mass
the masses of atoms are usually measured in _____
atomic mass units (u)
states that tiny particles like electrons do not absorb or release energy in a smooth flow
quantum theory
regions in which electrons move unpredictably
orbitals
the most familiar model of the atom
Bohr model
model of the atom that shows electrons have characteristics of both particles and waves
wave-mechanical model
states 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
a set of numbers that mathematically represent the overall motion of an electron
quantum numbers
says that no two electrons in an atom can have the same four quantum numbers
Pauli exclusion principle
the length of time required for one-half of the original substance to decay into a new substance
half-life
radioactive decay that occurs when a neutron in an atom’s nucleus changes into a proton, emitting an electron
beta decay
type of decay that increases the atomic number by one
beta decay
radioactive decay that occurs when an unstable atom ejects a clump of two protons and two neutrons
alpha decay
radioactive decay that occurs when an excited nucleus releases energy without a change in the number of protons or neutrons
gamma decay
type of decay that releases energy without a change in the number of protons or neutrons
gamma decay
the process whereby a heavy nucleus is split into several pieces by bombarding it with neutrons
nuclear fission
device that initiates an uncontrolled chain reaction
atomic bomb
a nuclear reactor that recycles spent nuclear fuel to produce more than it uses
breeder reactor
_____ initiates a controlled reaction
nuclear reactor
a device that harnesses controlled fission to produce useful energy
nuclear reactor
chain reaction cannot occur unless there is a certain amount of fissionable material present, called the _______
critical mass
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
the electrons in the outer shell of an atom
valence electrons
states that most atoms tend to react to obtain eight electrons in their valence shell
octet rule
states that elements show regular and repeating properties when they are arranged by their increasing atomic numbers
periodic law
table of the elements arranged by atomic number and number of valence electrons
periodic table of the elements
- a row of the periodic table
- a column of the periodic table
- period
- group
elements in groups 1,2, and 13-18
main-group elements
the left side of the periodic table is ______
metals
the middle of the periodic table is _______
semimetals
the right side of the periodic table is ______
nonmetals
elements in group 17
halogens
elements in group 2
alkaline earth metals
elements in group 1
alkali metals
elements in group 16
chalcogens
elements in group 18
noble gases
a basic constituent of all living things
carbon
most abundant element in the body
oxygen
second most abundant element in the human body
carbon
groups of two or more atoms linked by chemical bonds to form distinct units
molecules
a substance that has the same physical properties throughout and consists of only one type of atom
pure substance
a homogeneous mixture
solution
composed of several pure substances that are physically mixed but not chemically united
mixture
substance doing the dissolving
solvent
substance being dissolved
solute
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
molecules and compounds are composed of two or more atoms linked together by attractive forces called ______
chemical bonds
a chemical bond resulting from the sharing of valence electrons between atoms
covalent bond
occurs when two atoms share a single pair of electrons
single bond
occurs when two atoms share two pairs of electrons
double bond
occurs when two atoms share three pairs of electrons
triple bond
a diagram showing the locations of all the atoms and valence electrons
Lewis structure
