Question

40/20 Ca2+ hasa) 2O protons, 20 neutrons, and 18 electronsb) 22 protons, ?O neutrons, and 20 electronsc) 20 protons, 22 neutrons, and 18 electronsd) 22 protons, l8 neutrons, and 18 electrons

Answer 1

The common representation of atomic number, atomic mass and charge of an element is by writing in the following way:

40/20 Ca^2+

On the top, you have the atomic mass, which is the sum of the number of protons and the number of neutrons A = p + n

On the bottom, you have the atomic number, which is equal to the number of protons and number of electrons Z = p = e

The number and the sign indicate the charge of the element, if the element is +2, this means that we have a cation with 2 electrons missing, if the charge was -2, we would have an anion with 2 more electrons

Therefore the best answer for this question is:

20 protons, 20 neutrons, 18 electrons, letter A