The first 40 elements with their atomic numbers and symbols are listed below.
| Atomic number | Element | Symbol |
|—:|—|—|
| 1 | Hydrogen | H |
| 2 | Helium | He |
| 3 | Lithium | Li |
| 4 | Beryllium | Be |
| 5 | Boron | B |
| 6 | Carbon | C |
| 7 | Nitrogen | N |
| 8 | Oxygen | O |
| 9 | Fluorine | F |
| 10 | Neon | Ne |
| 11 | Sodium | Na |
| 12 | Magnesium | Mg |
| 13 | Aluminum | Al |
| 14 | Silicon | Si |
| 15 | Phosphorus | P |
| 16 | Sulfur | S |
| 17 | Chlorine | Cl |
| 18 | Argon | Ar |
| 19 | Potassium | K |
| 20 | Calcium | Ca |
| 21 | Scandium | Sc |
| 22 | Titanium | Ti |
| 23 | Vanadium | V |
| 24 | Chromium | Cr |
| 25 | Manganese | Mn |
| 26 | Iron | Fe |
| 27 | Cobalt | Co |
| 28 | Nickel | Ni |
| 29 | Copper | Cu |
| 30 | Zinc | Zn |
| 31 | Gallium | Ga |
| 32 | Germanium | Ge |
| 33 | Arsenic | As |
| 34 | Selenium | Se |
| 35 | Bromine | Br |
| 36 | Krypton | Kr |
| 37 | Rubidium | Rb |
| 38 | Strontium | Sr |
| 39 | Yttrium | Y |
| 40 | Zirconium | Zr |
Explanation
- The atomic number (Z) equals the number of protons in an atom’s nucleus; for a neutral atom it also equals the number of electrons.
- Elements are arranged in the periodic table by increasing atomic number; the table groups elements with similar chemical behavior into columns (groups) and rows (periods).
- Small mnemonic tips:
- First 10: H He Li Be B C N O F Ne — try memorizing them as short phrases (e.g., “Happy Henry Likes Beans Brown…” )
- Important transition metals in the 20s–30s include Ti (22), V (23), Cr (24), Mn (25), Fe (26), Co (27), Ni (28), Cu (29), Zn (30).
If you want, I can:
- provide electron configurations for each of the first 40 elements,
- give common oxidation states or uses,
- or make printable flashcards for studying. Which would help you most?