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Aleks Placement Test: Chemistry Exam/285 Questions & Answers
Aleks Placement Test: Chemistry Exam/285 Questions & Answers
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Aleks Placement Test:Chemistry Exam/285 Questions
& Answers
Matter - -Anything that has mass and takes up space; made of atoms
-Atoms - -Basic unit of matter which cannot be broken down and contain
mostly empty space; contains three parts: the electron, proton, and neutron
-Elements - -A pure substance that contains only one type of atom
-Compound - -Two or more elements that are chemically bonded; includes
ionic and covalent
-Mixture - -Two or more substances that are together but not bonded
-Pure Substance - -Substance that contains only one kind of compound
-Bose-Einstein Condensate - -The state of matter with the lowest energy;
basically a very cold solid
-Solid - -A state of matter with strong bonds
-Liquid - -A state of matter with weak bonds
-Gas - -A state of matter with no bonds
-Plasma - -The state of matter with the highest energy; it uses ionization
instead of bonds
-Robert Boyle - -First to define an element; any substance is a substance
unless it can be broken down
-John Dalton - -Used and combined previous ideas to discuss the atom;
elements are made of atoms; all atoms of an element are identical; atoms of
different elements are different; law of constant composition; atoms are
invisible
-Law of Constant Composition - -Atoms of one element can combine with
other elements to form compounds; a given compound always has the same
relative numbers and types of atoms
, -J.J. Thomson - -Discovered electrons and protons and developed the plum
pudding model of an atom
-Electrons - -The negatively charged particle in an atom; circles around the
nucleus in the electron cloud
-Proton - -The positively charged particle in an atom; located in the nucleus;
determine the element
-Neutron - -The neutral particle in an atom; it has no charge and is located
in the nucleus
-Plum Pudding Model - -A model of the atom that depicts a sphere of
positive charge with electrons scattered throughout
-Ernest Rutherford - -Conducted an experiment in which he shot alpha
particles at gold foil; roved there was a small, dense nucleus with a positive
charge and that protons are positive
-Metals - -Elements located on the left side of the periodic table that want
to lose electrons
-Characteristics of Metals - -- Malleable
- Ductile
- Conductive
- Lustrous
-Malleable - -The ability to be molded into shapes
-Ductile - -The ability to be pulled into wire
-Conductive - -The ability to allow heat or electricity to pass through an
object
-Lustrous - -The ability to be shiny
-Nonmetals - -Elements located on the right side of the periodic table that
want to gain electrons
-Metalloids - -Elements placed in a stair-step line between metals and
nonmetals; they have characteristics of both
-Diatomic Molecules - -Elements that occur in pairs in their natural state;
hydrogen, nitrogen, oxygen, fluorine, chlorine, bromine, iodine
, -Electronegativity - -The ability of a molecule to attract electrons to it;
increases as you move left to right in the table and decreases as you move
top to bottom; fluorine is the hardest
-Atomic Radius - -The radius of an atom; decreases as you move left to right
and increases as you move top to bottom
-Ionization Energy - -The energy needed to rip off an electron; increases as
you move left to right and decreases as you move top to bottom
-Ion - -An atom that has gained or lost electrons
-Anion - -An atom that gains electrons and has a negative charge;
nonmetals
-Cation - -An atom that looses electrons and has a positive charge; metals
-Isotope - -An atom that has changed its number of neutrons
-Atomic Number - -A unique number to each element that tells the number
of protons and the number of electrons if the atom is neutral
-Atomic Mass - -A number that tells the number of protons and neutrons in
an atom
-Neutron Number - -Atomic Mass - Atomic Number
-Radioactive - -A nucleus that spontaneously decomposes, forming a
different nucleus and producing one or more particles; alpha, beta, and
gamma ray
-Alpha Particle - -One type of radioactive particle; it is a essentially a helium
nucleus; when this type of particle is released, the mass of the atom is
conserved and so is the atomic number
-Beta Particle - -One type of radioactive particle; it is essentially an
electron; when this type of particle is released, the atomic mass is conserved
and the atomic number gains one (a neutron is changed to a proton)
-Gamma Ray - -One type of radioactive particle; it is a high energy photon
of light and is used to release excess energy; the atom is not changed at all
-Half-Life - -The time required for half of the original sample of nuclei to
decay; each radioactive nucleus of the same element has the same half-life;
the shorter the half-life, the more likely a nucleus will decay
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