Question

Which of the following given elements has one electron, one proton and no neutron?
A) H
B) Li
C) He
D) Cl

Answer 1

Every atom is made up of a nucleus and one or more electrons attached to it. One or more protons and a number of neutrons make up the nucleus. Only one kind of hydrogen, the most prevalent, lacks neutrons. The nucleus contains more than 99.94 percent of an atom's mass. The protons have a positive electric charge, whereas the electrons have a negative charge and the neutrons have none.

Complete answer:
The chemical element hydrogen has the symbol H and the atomic number 1. The lightest element is hydrogen. Under normal circumstances, hydrogen is a gas composed of diatomic molecules with the formula ${{H}_{2}}$ . It's odourless, colourless, non-toxic, and extremely flammable. Hydrogen is the most abundant chemical element in the universe, accounting for around 75% of all ordinary stuff.
The protons have a positive electric charge, whereas the electrons have a negative charge and the neutrons have none. The atom is electrically neutral if the number of protons and electrons is equal. When an atom contains more or fewer electrons than protons, it has a negative or positive overall charge, and these atoms are known as ions.
The number of protons in the nucleus of every atom of a chemical element is known as the atomic number or proton number (symbol Z). A chemical element's atomic number is the only way to identify it. It is the same as the nucleus' charge number. The atomic number is also equivalent to the number of electrons in an uncharged atom.
The mass number A of an atom is calculated by adding the atomic number Z and the number of neutrons N.
The atomic number of Hydrogen is (Z) = 1 and its mass number (A) is 1.
Therefore, the number of neutrons $=A-Z=0$ . Hence, it is represented by $_{1}{{H}^{1}}$
Hence option A is correct.

Note:
Except at extremely high pressures, hydrogen is nonmetallic and readily forms a single covalent bond with most nonmetallic elements, resulting in molecules like water and almost all organic compounds. Because acid–base interactions generally entail the exchange of protons between soluble molecules, hydrogen plays a particularly significant role.