Which statement concerning elements is true?
1. different elements must have different numbers of isotopes.
2. different elements must have different numbers of neutrons.
3. all atoms of a given element must have the same mass number.
4. all atoms of a given element must have the same atomic number.

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

every chemical equation adheres to the law of conservation of mass, which states that matter cannot be created or destroyed. therefore, there must be the same number of atoms of each element on each side of a chemical equation.

answer: i dont know the answer but this might

explanation:

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