The number of electrons in an atom's outermost valence shell governs its bonding behaviour. Elements whose atoms have the same number of valence electrons are grouped together in the Periodic Table. ... Nonmetals tend to attract additional valence electrons to form either ionic or covalent bonds.
Atomic mass / mass number / atomic weight
(all of which mean the same thing)
Answer:
Your answer is the first one about mountain ranges
Explanation:
When the earth split and pushed together, many mountain ranges were created
