Final answer:
To draw the Lewis dot diagram for an arsenic atom, first determine that it has 5 valence electrons from its electron configuration [Ar]4s²3d±04p³, then place dots around the symbol 'As' to represent these electrons, starting with single dots and pairing the fifth.
Step-by-step explanation:
To draw a Lewis dot diagram for an arsenic atom, you need to know the number of valence electrons in arsenic. Arsenic has the electron configuration [Ar]4s²3d±04p³, which means it has 5 valence electrons (the electrons in the 4s and 4p orbitals). Using the Lewis dot structure rules, you place one dot for each valence electron around the atom's symbol, starting with single dots and then pairing up any remaining dots after the first four.
For arsenic (As), the Lewis dot structure will have five dots placed around the symbol 'As': one above, one below, one to the left, and one to the right, and the fifth dot will be paired with one of the previous dots since it has more than four valence electrons. Thus, the structure will look something like this:
As
. .
• As•
.