How many valence electrons does each member of the boron family have

Express the following number in scientific notation. 0.026890 =

Which set of characteristics best describes igneous rock? a) largest type of rock, made of organic matter, hardest type of rock b) least abundant type of rock, made of other rocks, made mostly of minerals c) found on all continents, contains wavy bands of stripes, contains fossils d) most abundant type in earth's crust, made of magma/lava, contains no fossils

When a nucleus absorbs a neutron and then breaks apart, there are many products of the reaction. what is not a product of a nuclear fission reaction