Easy way to learn atomic mass of first 20 elements

Asked by admin @ 03/08/2021 in Chemistry viewed by 321 People

Trick to remember the atomic masses of first twenty elements of periodic table.

Answered by admin @ 03/08/2021

First twenty elements are , H, He , LI , Be , B , C , N , O , F , Ne , Na , Mg , Al , Si , P, S , Cl, Ar , K , and Ca
here
except :- Li , Be, B, F, Na , Al , P, Cl , K and Ar all atomic mass number is double the atomic number of it .
example :-
atomic no of CA = 20
so , mass no = 2× 20 = 40

# in Li , Be , B , F , Na , Al , and K
let atomic number of it is x
then mass number of it = 2x +1
example :-
atomic number of Al = 13
so, mass number = 2×13 +1 =27

# for Ar ( argon)
atomic no = x
then mass no =2x +4

# Chlorine
atomic no = 17
mass no = 35.5

"western music uses ____________ letters of the alphabet to indicate pitch. a) first five b) first seven c) wide variety d) last three"

Asked by maham237 @ 13/01/2021 in Arts viewed by 384 persons

The molar enthalpy of fusion for water is 6.008 kj/mol. what quantity of energy is released when 253g of liquid water freezes? (molar mass of water is 18.02 g/mol)

Asked by maham237 @ 10/01/2021 in Physics viewed by 334 persons

Easy way to learn atomic mass of first 20 elements

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