Question

in which of the following sets is the symbol of the element, the number of protons, and the number of electrons given correctly?
zn, 30 protons, 60 electrons
cs, 55 protons, 132.9 electrons
f, 19 protons, 19 electrons
in, 49 protons, 49 electrons

Explanation:

Step1: Recall the atomic number concept

The atomic number of an element is equal to the number of protons. For a neutral atom, the number of electrons is equal to the number of protons.

• For \(Zn\) (zinc), atomic number \(Z = 30\). So, number of protons \(=30\) and number of electrons \(=30\) (not \(60\)).
• For \(Cs\) (cesium), atomic number \(Z = 55\). Number of electrons (for neutral atom) should be \(55\) (not \(132.9\), as number of electrons and protons are integers).
• For \(F\) (fluorine), atomic number \(Z = 9\). So number of protons \(=9\) (not \(19\)).
• For \(In\) (indium), atomic number \(Z = 49\). So number of protons \(=49\) and for a neutral \(In\) atom, number of electrons \(=49\).

Answer:

In, 49 protons, 49 electrons.