How many inner, outer, and valence electrons are present in an atom of each of the following elements?
(a) o inner: 2 outer: 6 valence: 5
(b) sn inner: 46 outer: 4 valence: 4
(c) ca inner: 10 outer: 10 valence: 2
(d) fe inner: 12 outer: 14 valence: 2
(e) se inner: 28 outer: 6 valence: 5

answer: option (a) is the correct answer.

explanation:

the measurement of hydrogen ions in a solution is known as ph.

if ph of a solution is less than 7 then the solution is acidic. if ph of a solution is greater than 7 then the solution is basic.

when the ph of a solution equals 7, then the solution is considered as neutral.

the ph of pure water is 7, therefore, it means that concentration of hydronium ions equals that of hydroxide ions.