The Lewis structure of Carbon, helium, oxygen, phosphorus, hydrogen are shown in the image attached.
The Lewis structure of an element is a representation of how its valence electrons are arranged; these are usually represented as dots surrounding the elemental symbol. The element's position on the periodic table determines the number of valence electrons, which is represented by the number of dots.
For Oxygen , you would draw two dots on one side of the elemental symbol (O) to represent the electron configuration in the Lewis structure for oxygen (O), which has six valence electrons.