An atom has a negative charge. which of the following must have occurred?

a)it lost a neutron.
b)it lost an electron.
c)it gained a proton.
d)it gained an electron.

Marcel just purchased 1.69 grams of iron fillings in order to make living putty for his 6 year old niece. how many moles of iron are made in his sample?

Give more examples of this type of heat transfer:

Which of the following reasons best explains why a scientist would want to replicate gregor mendel's pea plant experiment? a. to discover new aspects of the natural world b. to test the predictions of current theories c. to explain recently observed phenomena d. to test the conclusions of prior investigations