Chemistry.

Hydrogen (H) has atomic number 1, the number of protons in its nucleus.

Helium (He) has atomic number 2, the number of protons in its nucleus.

Lithium (Li) has atomic number 3, the number of protons in its nucleus.

Beryllium (Be) has atomic number 4, the number of protons in its nucleus.

Boron (B) has atomic number 5, the number of protons in its nucleus.

Carbon (C) has atomic number 6, the number of protons in its nucleus.

Nitrogen (N) has atomic number 7, the number of protons in its nucleus.

Oxygen (O) has atomic number 8, the number of protons in its nucleus.

Fluorine (F) has atomic number 9, the number of protons in its nucleus.

Neon (Ne) has atomic number 10, the number of protons in its nucleus.

Sodium (Na) has atomic number 11, the number of protons in its nucleus.

Magnesium (Mg) has atomic number 12, the number of protons in its nucleus.

Aluminum (Al) has atomic number 13, the number of protons in its nucleus.

Silicon (Si) has atomic number 14, the number of protons in its nucleus.

Phosphorus (P) has atomic number 15, the number of protons in its nucleus.

Sulfur (S) has atomic number 16, the number of protons in its nucleus.

Chlorine (Cl) has atomic number 17, the number of protons in its nucleus.

Argon (Ar) has atomic number 18, the number of protons in its nucleus.

Potassium (K) has atomic number 19, the number of protons in its nucleus.

Calcium (Ca) has atomic number 20, the number of protons in its nucleus.

Scandium (Sc) has atomic number 21, the number of protons in its nucleus.

Titanium (Ti) has atomic number 22, the number of protons in its nucleus.

Vanadium (V) has atomic number 23, the number of protons in its nucleus.

Chromium (Cr) has atomic number 24, the number of protons in its nucleus.

Manganese (Mn) has atomic number 25, the number of protons in its nucleus.

Iron (Fe) has atomic number 26, the number of protons in its nucleus.

Cobalt (Co) has atomic number 27, the number of protons in its nucleus.

Nickel (Ni) has atomic number 28, the number of protons in its nucleus.

Copper (Cu) has atomic number 29, the number of protons in its nucleus.

Zinc (Zn) has atomic number 30, the number of protons in its nucleus.

Gallium (Ga) has atomic number 31, the number of protons in its nucleus.

Germanium (Ge) has atomic number 32, the number of protons in its nucleus.

Arsenic (As) has atomic number 33, the number of protons in its nucleus.

Selenium (Se) has atomic number 34, the number of protons in its nucleus.

Bromine (Br) has atomic number 35, the number of protons in its nucleus.

Krypton (Kr) has atomic number 36, the number of protons in its nucleus.

Rubidium (Rb) has atomic number 37, the number of protons in its nucleus.

Strontium (Sr) has atomic number 38, the number of protons in its nucleus.

Yttrium (Y) has atomic number 39, the number of protons in its nucleus.

Zirconium (Zr) has atomic number 40, the number of protons in its nucleus.

Niobium (Nb) has atomic number 41, the number of protons in its nucleus.

Molybdenum (Mo) has atomic number 42, the number of protons in its nucleus.

Technetium (Tc) has atomic number 43, the number of protons in its nucleus.

Ruthenium (Ru) has atomic number 44, the number of protons in its nucleus.

Rhodium (Rh) has atomic number 45, the number of protons in its nucleus.

Palladium (Pd) has atomic number 46, the number of protons in its nucleus.

Silver (Ag) has atomic number 47, the number of protons in its nucleus.

Cadmium (Cd) has atomic number 48, the number of protons in its nucleus.

Indium (In) has atomic number 49, the number of protons in its nucleus.

Tin (Sn) has atomic number 50, the number of protons in its nucleus.