How many valence electrons does group 18 have

group 18 has 8 valence electrons, that's why they are stable.

8!

Explanation:

You're looking at the very last column, right? Noble gases are known for their stability because their valence shells are full! Lucky for you, all you have to do to know the number of valence electrons is look at the column number and take ignore the 1! 16 becomes 6, 18 becomes 8.

when [oh-] is 10-5  m, and [h3o+] is 10-9  m, the poh is 5 and ph is 9. again in both cases the sum of ph and poh is 14. however, the hydrogen ion concentration is not always going to be equal to exactly 1 x 10 raised to a negative number. for example, we skipped over the value of 2.0 x 10-7.

let that person have a turn to speak : )