객관식An atom has an atomic number of 6 and a mass number of 14. How many neutrons does this atom have?155views
객관식Copper has two naturally occurring isotopes: copper-63 and copper-65. How many neutrons are present in an atom of copper-65?111views
객관식An isotope of the element fluorine has 9 protons and 10 neutrons. What is the name of this isotope?162views