What is Big Bang Nucleosynthesis? Approximately how hot was the universe at this time, and what kind of reaction did that allow for? At the end of the era of Nucleosynthesis what was the ratio of protons to neutrons, and how does that explain that more than 70% of the atomic mass of the Universe is in hydrogen?

What is the atomic mass of an atom that has 6 protons, 6 neutrons, and 6 electrons?

The question whether the universe will continue to expand, remain stable or collapse depends in part upon achieving a minimum density of 6.02x10^-27kg/m throughout the universe. How many neutrons, protons, and electrons per cubic meter are required to achieve this minimum density? Assume an equal number of protons and electrons, and 1.5 times as many neutrons as protons.

A certain atom has atomic number Z = 29 and atomic mass number A =60.

(a) How many protons and neutrons are in the nucleus?
(b) What is the approximate radius of the nucleus of thisatom?