What exactly are you asking
Explanation:
The number of protons in an atom is the atomic number.
Mass number is the number of protons plus neutrons in an atom.
Mass number = number of protons + number of neutrons
Atomic number = number of protons
Atomic number gives the symbol of the element
Number Number Atomic Mass Symbol
Protons neutrons Number Number
A 7 B 15 C
D E 26 56 F
A, number of protons = B
Mass number = protons + neutrons
15 = protons + 7
Protons = 15 - 7 = 8
Atomic number 8 is for oxygen = C
Atomic number = number of protons = D = 26
Number of neutrons ;
E = Neutrons = mass number - protons = 56 - 26 = 30
Atomic number 26 is for Iron = F
Molar mass Argon = 39.948 g/mol
1 mol ------ 39.948 g
mol ----- 20.0 g
mol = 20.0 * 1 / 39.948
= 0.5006 moles
1 mol --------------------- 22.4 L ( at STP )
0.5006 moles ------------- L
L = 0.5006 * 22.4
= 11.21 L
hope this helps!