The periodic table is called periodic because the of the elements repeat periodically?
The periodic table is layed out to show "Periodic" chemical properties such as the number of protons in the nucleus of the elemnt, and the number of valence electons it has.
When repeating chemical and physical properties of elements change periodically with the elements atomic numbers it is called the?
Because chemical properties periodically recur. That is, lithium has certain chemical properties, and 8 elements later is sodium, which has similar properties, and 8 elements after that is potassium, which again has similar properties. (It's not always 8; the next similar element is rubidium, which doesn't occur until 18 elements later, so it might better be called the "semi-periodic table of elements.")