The question requires us to identify how many electrons in an ion which contains 53 protons and it is located in the 17th column of the periodic table.
Atoms are made of three basic particles: protons, electrons and neutrons. The nucleus of the atom contains the protons (positively charged) and the neutrons (no charge), while the electrons (negatively charged) are located in the outermost regions of the atom.
We can determine the number o protons, electrons and neutrons in an atom with a set of simple rules:
- The number of protons in the nucleus of the atom is equal to the atomic number (Z);
- The mass number of the atom (M) is equal to the sum of the number of protons and neutrons in the nucleus and the number of neutrons is equal to the difference between the mass number of the atom (M) and the atomic number (Z);
- The number of electrons in a neutral atom is equal to the number of protons.
Knowing that the number of electrons in a neutral atom is the same as the number of protons, we can say that the neutral atom mentioned by the question contains 53 electrons.
Since the question mentions it is an ion, we need to consider its group in the periodic table to identify the charge of this ion and, therefore, identify the number of electrons it contains.
Elements in the 17th column of the periodic table, such as fluorine (F), chlorine (Cl) and bromine (Br), tend to receive one electron and form anions with charge -1.
Therefore, the ion mentioned by the question would present charge -1 and 54 electrons, since it receives one additional electron.