How many significant figures are in this number? : 2.7 x 10^-3

2 significant figures i.e. 2 and 7.

Explanation:

We need to find the number of significant figures in the given number i.e. .

It has 2 significant figures i.e. 2 and 7.

It means the power of 10 doesn't count in the significant figures.

Hence, there are 2 significant figures.

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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