Based on the clue 'atomic number 28 if you dont know 1 lb of pure thi...', what is the answer?

Based on the clue 'atomic number 10 this odorless gaseous element is ...', what is the answer? Based on the clue 'atomic number 13 you touch it when you unwrap a st...', what is the answer? What is referred to by 'atomic number 20'? Based on the clue 'atomic number 27 this silvery metallic element is ...', what is the answer? Based on the clue 'atomic number 30 its often used in sunscreen', what is the answer? Based on the clue 'atomic number 35 this element begins with the firs...', what is the answer? Based on the clue 'atomic number 9 its a trace element in the body no...', what is the answer? Based on the clue 'atomic particle paths can be tracked in this devic...', what is the answer?