Carbon-13 is an isotope of carbon. the atomic number of carbon is 6. how many neutrons does carbon-13 have?

Neutrons = mass no. - atomic no. Therefore depending on your periodic table (mine says 12 for mass number) so you do (mass no. - 6 = 6 or 7 ) depending again if you use 12 or 13

If a hydrogen atom is neutral, it must also have  one electron. an oxygen atom (o) has an atomic number of eight (8). this means a neutral oxygen atom has eight protons and eight electrons. the element actium (ac) has an atomic number of 89, so it has 89 protons and 89 electrons in a neutral atom

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