Question Answer
the number of electrons in the outermost shell that have the highest energy level and are held most loosely in place valence electrons
the number of __________ determines many properties of the element, including ways in which the atom can _________ with other atoms electrons/bonds
a symbol for an element surronded by dots the represent the number of __________ __________. It is a visual representation. valence electrons and this is the definition of a electron dot diagram
is a characteristic of a substance that can be observed without changing the substance into another substance physical property
give 3 examples of a physical property color, hardness, texture, shine, flexibility
is a characteristic of a substance that describes its ability to change into other substances chemical property
give 3 examples of a chemical property burning, tarnishing, rusting
is any change that alters the form or apperance of a substance but that does not make the substance into another substance physical change
give 3 examples of a physical change bending, breaking, cutting, crushing, phase change
is a change in matter that produces one or more new substances chemical reaction
give 3 examples of a chemical reaction burning, glow sticks, our reaction
a reaction in which energy is absorbed endothermic reaction
give an example of an endothermic reaction frying an egg
a reaction that releases energy in the form of heat exothermic reaction
give an example of an exothermic reaction fuel + oxygen changing into energy in an engine
a short, easy way to show a chemial reaction using symbols instead of words chemical equations
the small number following a chemical symbol that tells how many atoms there are of that element. If there is no number after the symbol it is understood to be one. subscript
are large numbers in front of an element that tell how many molecules there are of that compound coefficents
everything that goes into a chemical equation or what is on the left of the arrow reactants
everything that comes out of the reaction or is on the right side of the arrow products
shows that a chemical reaction has taken place. reads "yields" or "to produce" arrow
are used to separate two or more reactants or products. on the reactant side it is read as "combindes with" on product side it is read as "and" plus signs
states that during a chemical reaction matter is not created or destroyed. Whatever goes in on the reactant side must come out on the product side in the same amount. They can be in a different form. Conservation of mass
states that the total mass of the reactant must equal the total mass of the product. The principle of Conservation of Mass
is a chemical reaction in which some of the products escape and can’t be measured open system
is a chemical reaction that takes place in a contained setting where all products can be measured closed system
give an example of a open system fireplace
give an example of a closed system our reaction in ziploc
the same number of atoms of each element must be on each side of the equation. Golden Rule
the basic particle from which all elements are made atom
a neutral particle made of two or more atoms joined by covalent bonds molecule
a pure substance that cannot be broken down into other substances by physical or chemical means element
a pure substance made of two or more elements chemically combinde compound
name the 3 parts of the atom, where they are and what there charge is proton-in nucleus-positive charge neutron-in nucleus-no charge electron- in electron cloud- negative charge
force of attraction between two atoms chemical bond
what did Henri Becquerel discover? the effects of radioactive decay while studying a mineral containing uranium
What did Marie and Pierre Curie discover? radioactivity
the spontaneous emission of radiation by unstable atomic nucleus radioactivity
what 2 elements did Marie Curie discover? polonium & radium
consist of two protons and two neutrons with a positive charge alpha particle
fast-moving electron givin off by the nucleus during radioactive decay beta particle
consists of high-energy waves, similar to X-rays. Has no charge and does not change the atomic number or atomic mass gamma radiation
name the uses of radioactive isotopes tracing the steps in a chemical reaction and industrial process, and diagnosing and treating disease
are radioactive isotopes that can be followed through the steps of a chemical reaction or industrial process tracers

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