How valence electrons are arranged in a lewis dot diagram?

Explanation:

In a Lewis dot diagram, the electrons are arranged so that, when full, two electrons placed beside each other are on four sides of the element symbol.

An electron is 3-dimensional, so you can start on any side on a 2D diagram.

Continue this pattern depending on how many electrons you have:

When adding an electron after the first, it is placed on the next side going either counterclockwise or clockwise. Which ever direction you choose, be consistent.

After the fourth electron, so that one electron is on each side, place a dot beside your first electron and continue the pattern.

what is the general relationship between a galaxy's distance from earth and its speed?

the answer is:

the farther away a galaxy is from us, the faster it is moving away from us.

we can conclude that the melting point of table salt is above room temperature (it's actually 801 deg c). the melting point of mercury must be below room temperature (- 39 deg c).