52 terms

Chemistry Grade 9 Science

These definitions are based upon the Grade 9 Science Text Discovering Science 9, McGraw-Hill Ryerson as per the Newfoundland and Labrador Grade 9 Science curriculum, Unit 1.
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WHMIS
Workplace Hazardous Materials Information System
Toxic
mass
the amount of matter in a substance or an object
matter
anything that has mass and volume
volume
the amount of space taken up by a substance or object
element
a pure substance that can not be broken down into simpler components
chemical properties
characteristics that describe a substance's ability to react chemically with other substances to form new products
physical properties
a characteristic of matter that can be observed or measured
state
a physical property of a substance that describes it as either a solid, liquid, or gas
density
a physical property of a substance that is a ratios of the materials mass to it's volume D=m/V
combustibility
the degree to which a substance will burn
toxicity
the degree to which the substance reacts in the body to produce harmful substances
malleable
a physical property of a substance that refers to its ability to be bent or beaten into sheets
ductile
a physical property of a substance that refers to it's ability to be drawn into wires
atomic theory
an attempt to describe the nature of matter and explain how it behaves
atom
the smallest part of an element that still has the unique properties of that element
theory
an explanation of an event that has been supported by consistent, repeated experimental results and has therefore been accepted by most scientists, eg. the big bang theory
law
a description of events, patterns, or relationships in science that have been observed over and over again
nucleus
the positively charged center of an atom
John Dalton
proposed the Billiard ball model of the atom suggesting that all matter is made up of small spheres that are different for each element
J.J. Thomson
proposed the "Raisin Bun" model of the atom where the atom is a positive sphere with negative pockets of charge throughout
electrons
negatively charged particles that are located outside the nucleus of the atom and take up most of the space of an atom
Ernest Rutherford
proposed the "Plantary or Beehive" model of the atom with a positive nucleus containing protons and neutrons
proton
positively charged subatomic particles located within the nucleus with a mass of 1 AMU
neutron
neutral subatomic particles located in the nucleus of atoms having a mass of 1 AMU
Neils Bohr
proposed the "Orbital Model" of the atom where negatively charged electrons travel in fixed energy levels about a positively charged nucleus
subatomic particles
protons (+), neutrons (neutral), and electrons (-)
reactants
substances that react in a chemical reaction
products
substances that are created in a chemical reaction
chemical symbol
international symbol for each element consisting of one or two letters, the first is always capitalized
metals
elements left of the staircase on the periodic table that are hard, shiny, ductile conductors of heat and electricity
non-metals
elements on the right hand side of the periodic table that are brittle solids, gases or liquids at room temperature that do not conduct electricity or heat
metalloids
elements on either side of the staircase on the periodic table that have some metal and some non-metal properties (except Al which is a metal)
periodic table
organized list of elements arranged in rows and columns
atomic number
the number of protons in each atom of the element
atomic mass
the average mass of an atom of an element
chemical family
group of elements arranged in vertical columns on the periodic table with similar chemical and physical properties
alkaline earth metals
Column 2 on the periodic table; group makes bright coloured flames
alkali metals
Column 1 on the periodic table; reactive elements, especially with the halogen
halogens
Column 7A on the periodic table; reactive elements, could be solid liquid or gas
noble gas
Column 8A on the periodic table; nonreactive gases with full valence electron shells
transition metals
metallic elements found at the center of the periodic table
Bohr-Rutherford diagram
diagram of the atom that shows the number and location of electrons
energy level
the region surrounding the nucleus of the atom that contain a set number of electrons (2, 8, 8) maximums
chemical bonds
links between two or more atoms that hold the atoms together
covalent compounds
a compound formed when bond two atoms share a pair of electrons
ionic compounds
a compound formed from the transfer of electrons to create ions which then attract
molecule
the compound formed when atoms share electrons
chemical name
name of compound that indicates the elements in it
chemical formula
symbols that show the elements in a compound and their ratios
physical changes
a change in matter in which the appearance may change but no new chemical bonds are formed
chemical changes
a change in matter in which chemical bonds are formed and broken and at least one new substance is produced