The model below shows an atom of an element. 10 light gray and 8 dark gray balls sit at the center with 2 concentric black rings around them. The inner ring has 2 medium gray balls on it, and the outer ring has 6 medium gray balls on it. At bottom, a dark gray ball = +1, a light gray ball = 0, a medium gray ball = negative 1.

What is the atomic number of this atom?

6
8
9
16

Global warming will produce rising sea levels partly due to melting ice caps but also due to the expansion of water as average ocean temperatures rise. to get some idea of the size of this effect, calculate the change in length of a column of water 1.00 km high for a temperature increase of 1.00ºc. note that this calculation is only approximate because ocean warming is not uniform with depth. (answer in ×10^{-3} −3 m)