Answer
The Lewis symbol for $Al$ atom is shown below.
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)
1) $Al$ is in group 3A, so it has 3 electrons in the outermost occupied shell. Therefore, $Al$ has 3 valence electrons.
2) That means in the Lewis symbol, there will be 3 dots.
There are 4 places to put the 3 dots (top, bottom, right, left). But we would try to spread out the dots as much as possible, so each dot would occupy a place, leaving one place empty.
(The choice of which spot to fill the dots and which to leave empty is arbitrary. Here I would fill the right, left and bottom spot; and leave the top spot empty)
