How are elements related to the Earth's crust? The crust is composed of elements
Elements can only grow in the crust.
Elements are mined in the crust.
The crust creates elements

Covalent bonds generally form when the bonded elements have a difference in electronegativity less than 1.5. subtract the electronegativities for the following pairs of elements and predict whether they form a covalent bond. electronegativity difference of c and c: ionic covalent electronegativity difference of mg and cl: ionic covalent