Answer
The Lewis symbol for $As$ atom is seen in the diagram.
Work Step by Step
RULES TO WRITE LEWIS SYMBOL
- Find out the number of valence electrons in the atom.
- Write the element symbol and around it present each valence electron with one dot to the top, bottom, right or left of that symbol.
- Spread out the dots as much as possible (so there would be minimum electron-electron repulsions), and no spots can hold over 2 electrons.
1) $As$ is in group 5A, so it has 5 electrons in the outermost occupied shell. Therefore, $As$ has 5 valence electrons.
2) That means in the Lewis symbol of $As$, there will be 5 dots.
The first 4 dots would follow the rule to spread out and each would occupy an empty spot. So after the filling, each spot is filled with one dot.
The last dot now can occupy any spots. The choice is arbitrary.
Eventually, there are 1 spot with 2 electrons, and 3 spots with 1 electron.
