6. Which of the following elements is most likely to form covalent bonds when a molecule is formed?
A. He
B. Al
C. CI
D. Na
7. Which of the following elements are NOT likely to form chemical bonds?
A. Group 1 elements
B. Group 2 elements
С. Group 17 elements
D. Group 18 elements

8. All the following atoms can form negative ions in their compounds EXCEPT
A. Fluorine
B. Sulfur
C. Oxygen
D. Magnesium