if 0.5 ml of a 1:300 dilution contains 1 antigenic unit, 2 antigenic units would be contained in 0.5mL of a dilution of

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

answer:

technetium is the most reactive. this is followed by silver. the least reactive out of these three elements is strontium.

the answer is option a.