Ⓕⓘⓝⓓ ⓜⓔ ⓗⓔⓡⓔ�
Ⓢⓔⓧⓨ-ⓒⓗⓘⓚⓢ.ⓒⓛⓤⓑ

Name the element in group 17, period 2. (periodic table)

What is a substance? a. a physical property of matter b. a chemical property of matter c. an element or compound that cannot be physically separated d. characteristics used to tell the difference between mixtures

How many atoms or molecules are there in a mole of a substance?