Structure of The Atom:
Phosphorus
Atomic number: 15
Atomic mass: 30.97
Number of protons: 15
Number of electrons: 15
Number of neutrons: 16
Group number: 15
Valence electrons: 5A
Period number: 3
Family: Non-Metal
Atomic number: 15
Atomic mass: 30.97
Number of protons: 15
Number of electrons: 15
Number of neutrons: 16
Group number: 15
Valence electrons: 5A
Period number: 3
Family: Non-Metal
We know the atomic number is 15 because that's how it was labeled in the periodic table. Same with the atomic mass, that's what it says on the periodic table of elements. In order to find both protons (p+) and electrons (e-), they are equal to the Atomic Number. To find the neutrons (n°), we take the Atomic Mass (which is 30.974), round it to the nearest number (31), then minus the number of protons/electrons from the rounded mass (31-15) which equals to 16n°. The groups are arranged vertically, if you look on the periodic table, the number associated with Phosphorus is 15. The periods are arrange in a horizontally way, the number in the column of phosphorus is 3. Phosphorus is a non-metal hence why it's in that family.
