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.
A period 2 element is one of the chemical elements in the second row of the periodic table of the chemical elements. The periodic table is laid out in rows to illustrate recurring trends in the chemical behavior of the elements as their atomic number increases; a new row is started when chemical behavior begins to repeat, creating columns of elements with similar properties. The second period contains the elements lithium, beryllium, boron, carbon, nitrogen, oxygen, fluorine, and neon. This situ