Add single electrons and/or electron pairs as needed to complete the electron-dot symbol for astatine.

organisms are more likely to be more preserved in mud than sand because mud is moist and wet, while sand is very dry.

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.

practical process described pest part of scientific investigation.

because practical knowledge is powerful then therotical knowledge.