How to name the compounds in chemistry using roman numerals khan academy?

Which of the following pairs of elements belong to the same groupa. h and he b. li and bec. c and pb d. ga and ge

Which of these best describes an ionic bond?

In 1901, thomas edison invented the nickel-iron battery. the following reaction takes place in the battery. fe(s) + 2 nio(oh)(s) + 2 h2o(l) fe(oh)2(s) + 2 ni(oh)2(aq) how many mole of fe(oh)2, is produced when 5.35 mol fe and 7.65 mol nio(oh) react?