Answer
The Lewis symbol for $Sr$ 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) $Sr$ is in group 2A, so it has 2 electrons in the outermost occupied shell. Therefore, $Sr$ has 2 valence electrons.
2) That means in the Lewis symbol, there will be 2 dots.
Since each spot can hold up no more than 2 dots, 4 spots can hold up to 8 dots in maximum, with each spot holding 2 dots.
The rule is that the dots would spread out as much as possible. So obviously they do not clump into one spot. Instead, each dot would fill an empty spot.
Eventually, there are 2 spots with one electrons, and 2 empty spots.