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Aleks Placement Test. Chemistry Questions and Answers Graded A+
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Aleks Placement Test. Chemistry
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Aleks Placement Test. ChemistryMatter - answer Anything that has mass and takes up space; made of atoms
Atoms - answer Basic unit of matter which cannot be broken down and contain mostly
empty space; contains three parts: the electron, proton, and neutron
Elements - answer A pure substance that contains only one type of atom
Compound - answer Two or more elements that are chemically bonded; includes ionic
and covalent
Mixture - answerTwo or more substances that are together but not bonded
Pure Substance - answerSubstance that contains only one kind of compound
Bose-Einstein Condensate - answerThe state of matter with the lowest energy; basically
a very cold solid
Solid - answerA state of matter with strong bonds
Liquid - answerA state of matter with weak bonds
Gas - answerA state of matter with no bonds
Plasma - answerThe state of matter with the highest energy; it uses ionization instead of
bonds
Robert Boyle - answerFirst to define an element; any substance is a substance unless it
can be broken down
John Dalton - answerUsed 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 - answerAtoms 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 - answerDiscovered electrons and protons and developed the plum
pudding model of an atom
,Electrons - answerThe negatively charged particle in an atom; circles around the
nucleus in the electron cloud
Proton - answerThe positively charged particle in an atom; located in the nucleus;
determine the element
Neutron - answerThe neutral particle in an atom; it has no charge and is located in the
nucleus
Plum Pudding Model - answerA model of the atom that depicts a sphere of positive
charge with electrons scattered throughout
Ernest Rutherford - answerConducted 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 - answerElements located on the left side of the periodic table that want to lose
electrons
Characteristics of Metals - answer- Malleable
- Ductile
- Conductive
- Lustrous
Malleable - answerThe ability to be molded into shapes
Ductile - answerThe ability to be pulled into wire
Conductive - answerThe ability to allow heat or electricity to pass through an object
Lustrous - answerThe ability to be shiny
Nonmetals - answerElements located on the right side of the periodic table that want to
gain electrons
Metalloids - answerElements placed in a stair-step line between metals and nonmetals;
they have characteristics of both
Diatomic Molecules - answerElements that occur in pairs in their natural state;
hydrogen, nitrogen, oxygen, fluorine, chlorine, bromine, iodine
Electronegativity - answerThe 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 - answerThe radius of an atom; decreases as you move left to right and
increases as you move top to bottom
Ionization Energy - answerThe energy needed to rip off an electron; increases as you
move left to right and decreases as you move top to bottom
Ion - answerAn atom that has gained or lost electrons
Anion - answerAn atom that gains electrons and has a negative charge; nonmetals
Cation - answerAn atom that looses electrons and has a positive charge; metals
Isotope - answerAn atom that has changed its number of neutrons
Atomic Number - answerA unique number to each element that tells the number of
protons and the number of electrons if the atom is neutral
Atomic Mass - answerA number that tells the number of protons and neutrons in an
atom
Neutron Number - answerAtomic Mass - Atomic Number
Radioactive - answerA nucleus that spontaneously decomposes, forming a different
nucleus and producing one or more particles; alpha, beta, and gamma ray
Alpha Particle - answerOne 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 - answerOne 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 - answerOne 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 - answerThe 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
Percent Abundance - answerElements exist naturally in different isotopes, to the atomic
mass listed on the table is an average
Percent Abundance Equation - answerAverage Mass = (%)•(Mass of Isotope A) +
(%)•(Mass of Isotope B) +...
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