Pls answer as quick as possible pls. Assertion: Elements and compounds are pure substances.
Reason: Properties of compounds are different from those of its constituent elements. i) Both A and R are true and R is the correct explanation of the assertion.
ii) Both A and R are true but R is not the correct explanation of the assertion.
iii)A is true but R is false.
iv)A is false but R is true.

Darla claims that the first periodic table developed by mendeleev was not completely accurate, so it is not useful at all. harmony argues that it establish the periodic table we use today, making it more credible. who is correct and why? darla is correct, because a model that has any mistakes should be thrown out. darla is correct, because a good model would not need to change. harmony is correct, because mendeleev’s model had all of the information correct in the first version. harmony is correct, because mendeleev’s model made predictions that came true.

Which sentence from holes contains an implied personality trait? stanley and his parents had tried to pretend that he was just going away to camp for a while, just like rich kids do. he'd just been in the wrong place at the wrong time. stanley felt somewhat dazed as the guard unlocked his handcuffs and led him off the bus. stanley nodded to show he understood

Predict the relative bond lengths of the three carbon-oxygen bonds in the carbonate ion (co2−3). what would you expect the charge to be on each oxygen? match the words in the left column to the appropriate blanks in the sentences on the right. make certain each sentence is complete before submitting your answer.