1.6, 1.7, 1.8, 1.9

compound

- can be broken down into elements and has a fixed composition - a pure substance made up of two or more different elements in a fixed, characteristic chemical combination

mixture

- can be seperated into two or more components and has a variable composition of elements, compounds, or both

element

- cannot be broken-down into simpler substances, although different forms of an element are possible - one of the 100 or so pure substances in our world from which compounds are formed

coefficients

A small whole number that appears in front of a formula in a balanced chemical equation

Lothar Meyer

German chemist, also developed a periodic table at the same time as Mendeleev.

2006

When did Pluto lose its status as a planet

diatomic molecule

a molecule consisting of 2 atoms

subatomic particle

a particle that is less complex than an atom

chemical reactions

a process whereby substances described as reactants are transformed into different substances called products.

chemical equation

a representations of a chemical reaction using chemical formulas.

chemical formula

a symbolic way to represent the elementary composition of a substance

periodic table

an orderly arrangement of all the elements based on similarities in their properties

Plutonium

can fuel both nuclear reactors and nuclear bombs.

hydrocarbons

compounds made up only of the elements hydrogen and carbon

William Roentgen

discovered x-rays and received the first nobel prize in physics

metals

elements that are shiny and conduct electricity and heat well

nonmetals

elements that do not conduct heat or electricity well and have no one characteristic appearance

metalloids

elements that lie between metals and nonmetals on the periodic table and do not fall cleanly into either category.

law of conservation of matter and mass

in a chemical reaction, matter and mass are conserved. The mass of the reactants consumed equals the mass of the products formed.

subscripts

numbers written below the line that tell how many atoms of a given type are in a compound.

noble gas

one of the inert elements in Group 8A that undergoes few, if any chemical reactions

halogen

one of the reactive nonmetals in Group 7A, such as fluorine, chlorine, bromine, or iodine

chemical symbols

one- or two letter abbreviations for the elements. (atomic symbols)

groups

organize elements according to important properties that they have in common and are numbered from left to right.

valence shell

outermost electron shell

Nanotechnology

refers to the creation of the materials at the atomic and molecular (nanometer) scale

combustion

the chemical process of burning; that is, the rapid combination of fuel with oxygen to release energy in the form of heat and light

atoms

the smallest unit of an element that can exist as a stable, in pendent entity

molecule

two or more atoms held together by chemical bonds in a certain spatial arrangement