What happens if you add one proton to the nucleus of an atom?

Hint: To solve this question we first need to know what protons are. A subatomic particle that has a positive electric charge of +1 is known as a proton. It is contained in the atomic nuclei of the atom along with neutrons and together is known as nucleons.

Complete answer:
There is at least one proton present in the nucleus of each atom and hence is a necessary part of the nucleus. It also defines the property of an element.
Now, the atomic number Z of an element can be defined as the number of protons that are present in the nucleus of every atom of that element. The atomic number is also known as the proton number.
Every element has a unique and different number of protons present, and hence every element has a unique atomic number.
Now, the addition of a proton to an atom will increase its atomic number by one. Subsequently, the element will change and will be on the right of the parent element in the modern periodic table.
Now since the number of electrons is not being changed, the new element obtained will be an isotope.
For example, when a proton is added to the boron atom (that has 5 protons and 5 electrons in its neutral state), hypothetically an isotope of carbon is obtained.
\[_{5}^{11}B+p\to _{6}^{11}C\]
Naturally, the addition of protons to an atom happens in the sun where it generates energy by nuclear fusion of hydrogen atoms into helium atoms. This process takes place through the proton-proton chain reaction.

Note:
It should be noted that the addition of a proton to a nucleus artificially is extremely difficult. It requires a lot of energy that is generated in the form of kinetic energy.
One of the ways is using a particle accelerator in which atoms are accelerated to the speed of light and smashed together to create new elements and release energy.