Question

Atomic no. and mass no. of first 20 elements

Answer 1

Now that we understand what symbols, atomic numbers and atomic masses are, we are ready to focus on the first 20 elements of the periodic table.
A list of the first 20 elements is shown below:

ElementSymbolAtomic NumberAtomic MassNumber of ProtonsNumber of NeutronsHydrogenH1110HeliumHe2422LithiumLi3734BerylliumBe4949BoronB51156CarbonC61266NitrogenN71477OxygenO81688FluorineF91899NeonNe10201020SodiumNa11231112MagnesiumMg12241212AluminumAl13271314SiliconSi14281414PhosphorousP15311516SulphurS16321616ChlorineCl17351716ArgonAr18401822PotassiumK19391920CalciumCa20402020

Answer 2

Step-by-step explanation:

hope this helps you and have a good day.