Match the following descriptions to the person they describe: Mendeleev or Moseley.
| Mendeleev | arranged elements according to atomic mass |
| Mendeleev | predicted properties for elements missing from his periodic table |
| Moseley | English physicist, used x-ray diffraction |
| Mendeleev | had some elements out of place |
| Moseley | arranged elements according to atomic number |
| Moseley | discovered that each element has a unique atomic number |
| Mendeleev | Russian chemist, created first valid periodic table of the elements |
| Moseley | placed all elements in the right place according to properties |
What property is identical to the elements in each column of the periodic table?
Click to reveal the answer
Electron distribution – each element’s last term has the same number of electrons located in the same type of sublevel.
For example:
Li = 2s¹
Na = 3s¹
K = 4s¹
Write the noble gas configuration for each of the following elements. Highlight the table to reveal the answers.
| Lithium | [He]2s1 |
| Magnesium | [Ne]3s2 |
| Copper | Copper doesn’t follow the rules as expected. [Ar]4s13d10 |
| Bromine | [Ar]4s23d104p5 |
| Silver | Silver does not follow the rules as expected. [Kr]5s14d10 is the actual configuration. One 5s electron moves to the higher 4d sublevel because it is more stable there. |
| Tellurium | [Kr]5s24d105p4 |
| Uranium
(Hint: don’t forget the f-block!) |
[Rn]7s25f4 Remember that the principal quantam number is 2 fewer than the period number for electrons in f sublevels. |
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