Periodic Table

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First 20 Element

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)

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Atomic Numbers 1-20

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Atomic Mass 1-20

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Formulas

• number of protons = atomic number
• number of electrons = atomic number
• number of neutrons = mass number - atomic number

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Group Number

Groups are vertical columns, There are 8 groups which are labelled using Roman numerals, groups 1-7 are labelled with roman numerals 1-7 (I-vII) and group eight is labelled with a "O".

Group number is determined based on how much electrons are in the valence shell of an atom (outermost shell)

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Period Number

Periods are horizontal rows (we are interested in periods 1-4) which are represented using Arabic numbers (1,2,3,4...).

Period number is equal to the number of occupied electron shells in a particular atom.

Christopher Seebaran (pc)