Properties and Changes of Matter - Elements versus Compounds

Question 1

elements

Answer 1

• an element is a pure substance that cannot be sparated into simpler substances by physical or chemical means
• 92 naturally occurring elements
• indivisible
• seven elements are diatomic: O_2, N_2, H_2, F_2, Cl_2, Br_2, I_2
• names are represented by one, two, or three letter codes
• usually derived from name, but occasionally from the Latin

Question 2

compound

Answer 2

• a combination of two or more different elements that are combined chemically
• the properties of a compound are very different than its component elements
• NaCl, H_2O, C_6H_12O_6
• sodium and chlorine = sodium chlorine
• hydrogen and oxygen = water