| A | B |
|---|
| What is an element? | A substance that cannot be broken down into anything simpler. |
| How many elements re there? | about 100 |
| What is a compound? | A substance that is made up of 2 or more elements chemically combined. |
| water | H2O |
| carbon dioxide | CO2 |
| What is a mixture? | 2 or more substances mingled but not chemically combined |
| How is the mass of an element obtained? | By adding together protons and neutrons |
| What is the mass of a proton? | 1 amu |
| What is the octet rule? | When chemical bonding occurs atoms tend to reach an arrangement with 8 electrons in the outer shell. |
| What is a covalent bond? | A bond consisting of shared electrons |
| What is an ionic bond? | the force of attraction between oppositely-charged ions in a compound |
| What is an ion? | a charged atom or charged group of atoms |
| What is a molecule? | Two or more atoms chemically combined |
| What is the mass of a neutron? | 1 amu |
| What is the mass of an electron | 1/1840 amu |
| What does amu stand for? | atomic mass unit |
| What does the number of protons in an atom equal? | the number of electrons and the atomic number |
| The number of neutrons in an atom = | Mass number-number of protons |
| What is the atomic number of an atom? | The number of protons in the nucleus |
| What is an isotope? | An atom of the same atomic number but different number of neutrons |
