The isotope sodium-20 has how many protons?
Na
22.99
Sodium
O A) 9
OB) 10
OC) 11
OD) 12

Option A. 9

Explanation:

Isotope results when there is a change in the Neutron number of an atom.

From the question,

Mass number of the sodium isotope = 20

But the atomic number of isotopes are constant. Therefore, the isotope has:

Proton = 11

Mass number = Neutron + Proton

Neutron = Mass number — Proton

Neutron = 20 — 11 = 9

each chemical family is represented as a group or column on the periodic table. based on chemical properties, there are 6 types of chemical families. group 1 represents alkali metals, group 2 represents alkaline earth metals, groups 3 to 12 represent transition metals, groups 13 to 16 represent non-metals and other metals, group 17 represents halogens and group 18 represents noble gases.