Create an account
electrons in the outer most energy level of an atom; determine the chemical propeties of an element (ex. reactivity - how elements will react with other elements/compounds)
elements found on the left and center of the periodic table; usually solid, are shiny, conduct electricity, malleable
elements found on the right of the periodic table; usually gas, are dull, do not conduct electricity, brittle (not malleable)
elements located between metals and nonmetals on the periodic table (along bold stair-step line); have characteristics of both metals and nonmetals
rows in the periodic table; elements in same period have same number of energy levels; elements in same period are not alike in properties
columns in periodic table; also known as "families"; elements in same group have similar physical and chemical properties because they have the same number of valence electrons
Physical Properties of Matter
how matter is described according to physical characteristics; characteristics that can be observed without changing the substance into something else; ex. luster
Chemical Properties of Matter
characteristics that can be observed when a substance interacts with another substance; ability to react; inability to react; usually hidden
Physical Changes in Matter
a change in the form or appearance of a material that does not change it into a new substance; a change in size, shape, or state of matter; no new matter is formed; ex. melting ice, tearing paper, dissolving kool-aid, mixing salt and pepper, muscles of stomach grind food into smaller pieces
Chemical Reaction (Chemical Changes in Matter)
atoms are rearranged to make new substances with new properties different than the original substance; starts with reactants, ends with products; ex. rusting nails, decaying matter, burning wood, digesting food is mixed with acid in digestive systemt to break down protein molecules (carbohydrates broken down into sugars)
Evidence of Chemical Reaction
-production of gas
-formation of precipitate
-change in temperature
-change in color
-change in odor
way of describing elements and number of atoms that make up one molecule of a compound; uses symbols, subscripts and coefficients
way of writing changes in the arrangement of atoms during a chemical reaction; uses symbols, subscripts and coefficients; balanced when equation has the same number of atoms of each element on both sides of the equation
Law of Conservation of Mass
matter can neither be created nor destroyed, it can only change form; the mass of all substances before a chemical reaction must equal the mass of all substances after a chemical reaction
top number in the element square on the periodic table; identifies the number of protons and electrons in a neutral atom
decimal number found beneath the symbol in the element square on the periodic table; usually rounded off to find the number of neutrons
Finding the Number of Protons or Electrons in an Atom
look at the atomic number on the periodic table
Finding the Number of Neutrons in an Atom
round off the atomic mass to the nearest whole number and subtract the atomic number from it.
a pure substance consisting of only one kind of atom and identified by its' atomic number (which is the number of protons).
compounds containing carbon, as well as hydrogen and/or nitrogen, sulfur, phosphorous, or oxygen. (Used for life processess, make up nucleic acids, proteins, carbohydrates)
A diagram shaped like a TRIANGLE that shows the loss of energy at each level of the food chain
Please allow access to your computer’s microphone to use Voice Recording.
Having trouble? Click here for help.
We can’t access your microphone!
Click the icon above to update your browser permissions and try again
Reload the page to try again!Reload
Press Cmd-0 to reset your zoom
Press Ctrl-0 to reset your zoom
It looks like your browser might be zoomed in or out. Your browser needs to be zoomed to a normal size to record audio.
Please upgrade Flash or install Chrome
to use Voice Recording.
For more help, see our troubleshooting page.
Your microphone is muted
For help fixing this issue, see this FAQ.
Star this term
You can study starred terms together