3. You are a chemistry student and are given only a formula of a compound. Your job is to identify whether the compound is held together by ionic or covalent bonds(HINT: look at your notes to see what the definition of each bond is. You will need a periodic table too.)

the correct option is c.

isotopes refers to different forms of the same element with the same atomic number but different mass number as a result of difference in their neutron numbers. isotopes have different relative atomic mass but share the same chemical properties.

space exploration has led to the development and technological improvement of many everyday items. (if this answer is wrong i will find the right answer) : )