You add them and then subtract them
It is c because I did it already
1. D
2. A
3. B
4. C
5. E
6. I
7. J
8. L
9. M
10. G
11. H
12. K
13. F
They have strong intermolecular forces between their atoms, hence why more heat is necessary.
The answer is D
Calcium has two electrons in its outer energy shell
