1. a single chemical compound or element that is found in nature amorphous 2. the amount of kinetic energy that a material can absorb without breaking cleavage 3. a break that does not follow a flat surface, but rather is rough and uneven crystal 4. resistance to being scratched fracture 5. a solid form resulting from the arrangement of atoms, ions, or molecules in definite geometric patterns hardness 6. a clean break parallel to planes of weakness in a crystal mineral 7. a non-crystalline solid having no orderly arrangement of molecules toughness

answer:

the answer is 6 valence electrons.

explanation:

valence is the # of electrons on the outer most shell of an atom.

oxygen has 6.

although, the valency of oxygen is 2, because it only needs to make 2 covalent bonds, or gain 2 electrons, to achieve the stable octet configuration of a noble gas.

that's it!

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~ trueboss72

substituting a hydrogen atom with a halogen in a hydrocarbon:

- the single bond remains single. a is wrong.

- the bond with hydrogen is as strong as with a halogen. c is wrong

- a hydrocarbon is saturated if there is no double bond. we do not know that so d is wrong.

- carbon will always have four valence electrons. e is wrong.

by elimination, the correct answer is b. the boiling point of the new compound increases.