| A | B |
|---|
| atom | the smallest particles of matter |
| electrons | invisble, negatively charged subatomic particles |
| protons | positively charged subatomic particles |
| isotopes | same number of protons, different # neutrons |
| neutron | a neutral subatomic particle |
| nucleus | the small dense, positively charged core of an atom |
| atomic number | the number of protons in an element |
| mass number | sum of protons & neutrons of an atomn |
| metals | good conductors of heat and electricity |
| non-metals | usually dull; poor conductors |
| metalloids | these elements have characteristics of both metals & nonmetals |
| substance | sample of matter that has the same composition & properties throughout |
| compound | example: salt (NaCl), water (H2O) |
| mixture | two or more substances that have not combined to form new, pure substance |
| uniform mixture | examples: air, blood, ice tea |
| non-uniform mixture | example: trailmix |
