Chemistry

element

substance that CANNOT be chemically broken down into simpler substances

atom

smallest part of an element that can be identified as that element

nucleus

center, or core, of an atom (where the protons and neutrons are located)

proton

particle that has a positive charge - located in the nucleus of an atom. You can figure out the number of protons by looking at the atomic number of an element.

neutron

particle that has no charge - located in the nucleus of an atom. You can figure out the number of neutrons by SUBTRACTING the atomic Mass minus the atomic number.

electron

particle that has a negative charge - located in rings outside the nucleus of an atom. You can figure out the number of electrons by looking at the atomic number of an element.

atomic number

number of protons in the nucleus of an atom. This is the same number as the number of electrons

atomic mass

total mass of the protons and neutrons in an atom

energy level

place in an electron cloud where an electron is most likely to be found - rings. Remember, 2-8-18-32.

metal

element that has the property of shiny luster, ductility, and malleability

luster

the way a material reflects light

malleable

able to be hammered into different shapes

ductile

able to be drawn into thin wires

nonmetal

element that lacks most of the properties of a metal, is not shiny, does not conduct electricity or heat well, is not malleable so it is called brittle or breakable.

halogens

elements that make up Group 17 in the periodic table

noble gases

elements that make up Group 18 in the periodic table

matter

anything that has mass and takes up space

properties

characteristics used to describe an object

state of matter

any of the four physical forms of matter

solid

state of matter with a definite shape and volume

liquid

state of matter with a definite volume but no definite shape

gas

state of matter that has no definite shape or volume

plasma

state of matter made up of electrically charged particles - needs high temperatures and high pressure

chemical formula

way of writing the name of a compound using chemical symbols

subscript

number written to the lower right of a chemical symbol in a chemical formula

chemical equation

statement in which chemical formulas are used to describe a chemical reaction

coefficient

number that shows how many molecules of a substance are involved in a chemical reaction

chemical reaction

process in which new substances with new chemical and physical properties are formed

reactant

substance that is changed in a chemical reaction

product

substance that is formed in a chemical reaction

molecule

smallest part of a substance that has all the properties of that substance - more than one element, like hydrogen and oxygen make water

chemical bond

force of attraction that holds atoms together

freezing

change from a liquid to a solid

melting

change from a solid to a liquid

evaporation

change from a liquid to a gas at the surface of the liquid

condensation

change from a gas to a liquid

sublimation

change from a solid directly to a gas

physical change

change that does not produce new substances - melting an ice cube or ripping paper. You can get the ice back and the paper is still paper.

chemical change:

change that produces new substances - burning wood to make ashes or mixing mentos and coke. You can't get the wood or the mentos back.