Question

If an atom has an atomic number of 9 and an atomic mass number of 19, how many protons, neutrons, and electrons does it have?

Answer 1

Hint: As we know that protons are positively charged, electrons are negatively charged. If we have to find the number of neutrons, we will subtract the atomic number from the mass number. And we can easily find the electrons, neutrons and protons.

Complete answer:
- As we all know that atomic number denotes the total number of protons present in the nucleus of an atom. As we are provided with the information that the mass number of fluorine is 19, and we know that the atomic number of fluorine is 9.
- It is found that the number of protons is equal to the atomic number. This clearly means that any atom which is an isotope of fluorine will basically have 9 protons in the nucleus.
- And the number of electrons is equal to the proton number. Hence, we can say that there will be 9 electrons.
- Now, we will calculate the number of neutrons present. As we know that mass number= number of protons + number of neutrons. Hence, the number of neutrons will be = 19-9=10.
- Hence, we can conclude that there are 9 electrons, 9 protons, and 10 neutrons fluorine have.

Note:
- We should note that the total number of neutrons present in the nucleus is equal to the difference between the atomic number and the mass number of an atom.
- As we know that the mass number of any atom is basically equal to the addition of the protons and neutrons that are present in the nucleus.