The Atomic Number and Atomic Mass of ²⁸Si₁₄ are 14 and 28 respectively.
Atomic Number: Atomic Number of Element is the Number of Protons contained by the Element. So, there are 14 Protons in ²⁸Si₁₄.
Atomic Mass: Atomic Mass of Element is the total number of Protons and Neutrons present in the Nucleus of that element. So, Atomic Mass = # of Protons + # of Neutrons
As the Atomic mass of ²⁸Si₁₄ is 28 and it has 14 protons, So # of Neutrons are calculated as,
# of Neutrons = Atomic Mass - # of Protons
# of Neutrons = 28 - 14
# of Neutrons = 14
Result: In ²⁸Si₁₄ Number of Neutrons are 14, Number of Protons are 14.