What element is representing by the letter O?, oxygen, gold, iron, sodium, Oxygen has the atomic number of ______?, 9, 8, 7, 6, Atomic number is described as __________, as the number of the element symbol, as the number of protons in an atom, the same as element name, the element outside the box, Why are elements arranged according to atomic number in the periodic table?, To separate metals from nonmetals, To make the table colorful, To group heavy elements only, To show increasing number of protons, Which statement BEST shows appreciation of the importance of elements?, Elements have no effect on daily life, Elements help explain how medicines, gadgets, and materials work, Elements are only useful to scientists, Elements are hard to understand.

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