**Mnemonic Device:**

- Happy Henry Lives Beside Boron Cottage, Near Our Friend Nelly Nancy MgAllen. Silly Patrick Stays Close. Arthur Kisses Carrie.
- Here He Lies Beneath Bed Clothes, Nothing On, Feeling Nervous, Naughty Margret Always Sighs, ” Please Stop Clowning Around ” (18 elements)
- How He Likes Bear By Cups Not Overflowing. Although Science Presents Some Clues, Are Kittens Cats?

**Explanation:**

Happy. – H Hydrogen

Henry – He Helium

Lives – Li Lithium

Beside – Be Beryllium

Born – B Boron

Cottage – C Carbon

Near – N Nitrogen

Our – O Oxygen

Friend – F Fluorine.

Nelly – Ne Neon

Nancy – Na Sodium

Mg – Mg Magnesium

Allen – Al Aluminum

Silly – Si Silicon

Patrick – P Phosphorus

Stays – S Sulphur

Close – Cl Chlorine

Arthur – Ar Argon

Kisses – K Potassium

Carrie – Ca Calcium

**Additional Information:** the first twenty elements, of the periodic table, with their atomic number

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. flourine 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

**Find the average atomic mass:**

Rules to find the average atomic mass, if the atomic number (Z) is an:

Even number except Be (9), Ar (40),

- multiply the atomic number by 2. For example,
- 1) Helium atomic number (Z) is the EVEN #2, hence to find the average atomic mass (A) is (Atomic number) multiply by 2 which is 2 x 2 = 4

Odd number except H (1), N (14 ), Cl (35.5),

- multiply the atomic number by 2, then add 1. For example,
- 1) Lithium atomic number (Z) is the ODD # 3, hence to find the average atomic mass (A ) is (Atomic number) multiply by 2 plus 1, which is 3 x 2 +1 = 7
- 2) Boron atomic number (Z) is the ODD # 5, hence to find the average atomic mass (A ) is (Atomic number ) multiply by 2 plus 1, which is 5 x 2 +1 = 11

Please remember the exception to the rules:

- Be, Ar, H, N, Cl

**Song for the first 20 elements: **

**Many more mnemonics for remembering the elements of the periodic table**

See https://en.wikipedia.org/wiki/Periodic_table for more information.

Each n every1 must learn

That really, really helped me be able to get an 100% on my science test on the first 20 elementsin the perodic table. My teacher commented to me and said, “did you cheat”:)

Thanx a lot very much ?? u made it easier bro ??