How do you work out the name of this structure from the skeletal formula?

Asingle atom of an element has 21 neutrons, 20 electrons, and 20 protons. which element is it? ok o z

Ted and emily played a mixed doubles tennis match against jack and brenda. in the second match. ted and brenda played against jack and emily. which type of chemical reaction does the situation demonstrate?

Is 9 correct? and can someone me with 10? it’s due tomorrow, you