And the service in these stores is also very good. Generally, the price of an eye exam in Wal-mart, Costco and Target optical can range from less than $50 (if you have an eye exam at a retail store or optical chain) to $100 or more (if you have an eye exam at a medical clinic or private eye doctor's office).
What is true about the elements of a period? (Select all that apply.) a.They have the same number of electron shells. b They have similar chemical characteristics. c They have similar physical characteristics.
Periods (rows) are the horizontal arrangements of the elements. . Elements in the same Period have the same number of occupied electron shells (energy levels) . There are seven (7) periods on the Periodic Table of the Elements. Periodic Law: The properties of the elements are periodic function of their atomic numbers. In other words, by arranging the elements in the order of increasing atomic numbers, elements with similar. properties end up in the same group.