1 Write the correct symbol, with both superscript and subscript, for each of the following. Use the list of elements in the front
inside cover as needed: (a) the isotope of platinum that contains
118 neutrons, (b) the isotope of krypton with mass number 84,
(c) the isotope of arsenic with mass number 75, (d) the isotope of
magnesium that has an equal number of protons and neutrons.

in 1783 cavendish was working with his hydrogen gas and found that when he burned it and condensed the vapor it was water. this was very significant since it disproved the greek theory of elements completely since water was not a simple substance but the product of two gases. it was lavoisier who hearing of the experiment gave cavendish's gas the name hydrogen ("water-producer") and added that hydrogen burned by combining with oxygen and that water was a hydrogen-oxygen combination.

explanation:

they it depends on if one believes about radioactivity, they make a geiger counter beep but maybe it was going to beep anyway electronics do wierd things all the time or it was programmed to beep near certain metals.