Question | Answer |
Define allotrope | Elements that come in different forms |
Example of an allotrope | Carbon |
Name 9 physical characteristics of elements | color, odor, state, solubility, malleability, ductility, freezing point, melting point, melting point |
Who was given credit for creating the periodic table? | A Russian scientist named Dmitri Mendeleev |
Why was Dmitri Mendeleev given credit for discovering the table? | He predicted almost accurate properties for elements that had not yet been discovered. |
What was Mendeleev's table based on? | Increasing atomic mass |
What is the current table based on? | Increasing atomic number |
Who changed the table? When? | A British scientist named Henry Moseley in 1913 |
Who was the German scientist who was working on creating the table around the same time as Mendeleev? | Lothar Meyer |
Define atomic number | The number of protons in an atom's nucleus |
Define atomic mass | The number of neutrons and protons (nucleons) in an atom's nucleus. |
What are vertical columns in the table called? | Groups or families |
How many families are there in the table? | 18 |
What are the horizontal rows in the table called? | Periods |
How many periods are in the table? | 7 |
What is Group 1 called? | alkali metals |
What is Group 2 called? | alkaline earth metals |
What is Group 17 called? | halogens |
What is Group 18 called (both names)? | inert gases or noble gases |
What are elements located left of the staircase called? | metals (besides hydrogen) |
What are the elements located to the right of the staircase called? | non-metals |
What are the elements that border the staircase called? | metalloids (besides aluminum and polonium) |
How many metalloids are there? | 7 |
What are the large group of elements in the center of the table (Groups 3-12) called? | transition metals |
What are the elements located at the bottom of the periodic table called? | rare earth metals |
How many elements are there? | 118 |