Question #5f1e8

2 Answers
Jan 12, 2018

#20gmol^-1#

Explanation:

Protons and Neutrons both have a RELATIVE atomic mass of 1#gmol^-1#.

Electrons are considered to have no RELATIVE atomic mass and thus the overall relative atomic mass of an element is the total number of protons and neutrons present.

In this case, 10 protons and 10 neutrons = 20.

Jan 13, 2018

If mass number, or atomic mass number, is what is meant in this question, the mass number of a neon atom with 10 protons, 10 neutrons, and 10 electrons, is 20. Its symbol is #""^20"Ne"#.

Explanation:

The mass number of an isotope is the sum of its protons and neutrons. Electrons are not included in mass number because the mass of an electron is so tiny that its considered negligible for this purpose.