WordPress HTML editor panel is not showing HTML elements

Question

The problem

After typing my post/page in the visual editor, when I switch to the HTML editor, the expected HTML elements do not show. Headings appear but paragraphs and divs do not.

A minority of people have suggested that only one editor can be used.

My question

1. Can I not interchange between the visual and HTML tabs when writing a post/page?
2. Why can't I view the HTML elements?