To make its second-highest energy level be its valence energy level (being filled with an octet of electrons) and possess a more stable electronic arrangement, a strontium atom could form an ionic bond with two oxygen atoms.

False

Explanation:

The result after this ionic bond will not be as was stated in the question which makes this false.

explanation:

let the different atoms be x and y. each with four protons and same mass will be represented as follows.

mass number is number of protons + number of neutrons.

            and  

since, it is given that one has a negative charge while the other is neutral. therefore, there will be increase in number of protons and the atom will be represented as follows.

according to periodic table, mass number of beryllium is 9 and it has atomic number 4 so, the atoms will be and .  

the protons and neutrons will be located inside the nucleus whereas the electrons will be revolving around the nucleus.  

i believe the answer is 5,000