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
f, 19 protons, 19 electrons
cs, 55 protons, 132.9 electrons
in, 49 protons, 49 electrons

Explanation:

• For a neutral atom, the number of protons equals the number of electrons.
• The atomic number of an element gives the number of protons.
• For \(Zn\) (zinc), atomic number \(Z = 30\). In a neutral \(Zn\) atom, number of electrons \(=30\) (not \(60\)).
• For \(F\) (fluorine), atomic number \(Z = 9\) (not \(19\)).
• For \(Cs\) (cesium), atomic number \(Z = 55\). In a neutral \(Cs\) atom, number of electrons \(=55\) (not \(132.9\), \(132.9\) is the atomic mass).
• For \(In\) (indium), atomic number \(Z = 49\). In a neutral \(In\) atom, number of protons \(=\) number of electrons \(=49\).

Answer:

In, 49 protons, 49 electrons.