Chapter 5 Flashcards
Empedocles
4 elements: earth, air, fire, and water
Democritus
tiny invisible particles called “atoms”
Dalton’s Atomic Theory
- elements are composed of atoms
- atoms of same element are same in mass & size
- atoms of diff. elements are diff. mass & size
- chemical compounds are formed by 2+ atoms of diff. elements
- atoms combine to form compounds in simple ratios
- atoms of 2 elements may combine in diff. ratios to form multiple compounds
Law of Definite Composition
a compound always contains 2+ elements combined in a definite proportion by mass
Law of Multiple Proportions
atoms of 2+ elements may combine in diff. ratios to produce more than 1 compound
ion
an atom carrying a + or - electric charge
Electrons
-
form shell of atom
small mass
Protons
+
in of nucleus of atom
large mass
Neutrons
No Charge
in of nucleus of atom
slightly more mass than proton
positive ions
neutral atom loses electrons, protons have extra + charge
negative ion
electrons can be added to atoms, extra electrons have extra - charge
Cation
1 or more electrons are lost from an atom
Anion
1 or more electrons are added to a neutral atom
Allotropes
solid nonmetal elements that exist in diff. forms with diff. physical properties