Multiple ChoiceHow many elements on the periodic table are known to occur naturally on Earth?117views
Multiple ChoiceIn the following diagram, the element with atomic number 8 is represented by a question mark. Which element's symbol should replace the question mark?105views
Multiple ChoiceIn the periodic table, the element manganese is represented by a box containing the symbol 'Mn'. If an arrow is pointing to 'Mn', what does this symbol indicate?144views
Multiple ChoiceWhich of the following element symbols represents the element found in mercury?98views
Multiple ChoiceWhich element is in the same period as ruthenium (Ru) but has a higher atomic number than ruthenium?137views