valence electrons are the number of electrons in the outer shell. there can only be 8 electrons in the outer shell. The number of valence electrons can be used to determine how many bonds are needed.
For example: H2O
O (oxygen) has 6 valence electrons
H (hydrogen) has 1 valence electron
O needs 2 more electrons to be stable
H needs 1 more electron to be stable
O forms one bond with two H atoms to form H2O.
The answer is 23, 040 minutes. To solve this you can start by changing days in to hours. We know that there are 24 hours in a day. To find how many hours are in 16 days you multiply 24 by 16 which is 384. Next you must find out how many minutes are in 384 hours. we know there are 60 minutes per hour. To find how many minutes are in 384 hours, you multiply 384 by 60. To this you get 23, 040 which is your answer.
Since tasting or touching the texture or surface could be deemed unsafe. It would be best to use a pH meter or litmus paper. pH meter will accurately determine pH. Litmus paper if red will be acidic and basic if blue. You can also perform conductivity test. Else, you can also perform hydrogen test.