Which mineral is hard enough to scratch calcite? * 1 talc
2 sulfur
3 halite
4 quartz

Should be number 4, quartz.

Explanation:

Quartz is rougher than calcite, therefore it's able to scratch it.

away from the curb

explanation:

the wheels would then hit the curb if it started to rolling, decreasing the chance of an accident.

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!

if you need further assistance, let me know: )

~ trueboss72