Isotopes of different elements have different weights. to calculate the atomic mass for that element, you must find the
a.
atomic mass number
b.
weighted average
c.
periodic group

a. they are both space stations

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1. they vary with a higher number because boiling is way hotter than melting

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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