"A nuclear reaction of significant historical note occurred in 1932, when a beryllium target was bombarded with alpha particles. Analysis of the experiment indicated that the following reaction occurred: 4 2He + 9 4Be → 12 6C + ? What is missing in this reaction?"

Which type of bond is present in hydrogen sulfide (h2s)? the table of electronegativities is given. a. hydrogen b. ionic c. nonpolar covalent d. polar covalent

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 of these would be caused by a chemical change? a) the formation of lava. b) sedimantary rock layering over time. c) metamorphic rock forming from igneous. d) metamorphic rock eroding to form sedimentary rock.