Question

Calculate the number of protons, electrons, and neutrons in an atom of the element Pb with mass number 207 and atomic number 82.

Answer 1

Answer:p=82,e=82,n=125.

Explanation:

Let $p$ be the number of protons.

Let $e$ be the number of electrons.

Let $n$ be the number of neutrons.

Atomic number is defined as the number of protons in a atom or ion.

Given,atomic number is $82$.

So,$p=82$

Since the atom is electrically neutral,number of protons and electrons are equal.

So,$e=p=82$

The atomic mass is the sum of neutrons and protons.

$n+p=207\\n=207-82\\n=125$