Question

protons: 3
neutrons: 4
electrons: 3
14
si
silicon
28.09
protons: 14
neutrons:
electrons:

Explanation:

Step1: Recall atomic number and mass - number relationship

The atomic number of an element is equal to the number of protons. For silicon (Si), the atomic number is 14, so the number of protons is 14. The mass - number is approximately the sum of protons and neutrons. The mass number of Si is approximately 28 (from the atomic mass 28.09, we can consider the whole - number part for a rough estimate).

Step2: Calculate the number of neutrons

Let the number of neutrons be $n$, the number of protons be $p$, and the mass number be $A$. We know that $A=p + n$. Given $A\approx28$ and $p = 14$, then $n=A - p=28 - 14 = 14$.

Step3: Determine the number of electrons

In a neutral atom, the number of electrons is equal to the number of protons. Since Si is a neutral atom and the number of protons is 14, the number of electrons is 14.

Answer:

Neutrons: 14
Electrons: 14