Which of these statements is not true?
a. atoms of the same elements can have different masses.
b. the nucleus of an atom has a positive charge.
c. atoms of isotopes of an element have different numbers of protons.
d. atoms are mostly empty space.

What type of nuclear decay causes the atomic number of an element to increase by 1?

Which is not one of the major climate zones? question 3 options: rain forest polar tropical temperate

(a) calculate the number of electrons in a small, electrically neutral silver pin that has a mass of 10.0 g. silver has 47 electrons per atom, and its molar mass is 107.87 g/mol. (b) imagine adding electrons to the pin until the negative charge has the very large value 1.00 mc. how many electrons are added for every 109 electrons already present