It's these two numbers, 20 and 13, that are used to make up the Tzolk'in calendar, the first calendar used by the Mayans. 1  1. 2  2. 3  3. 4  4. â¦. 5  5. 6.  NEXT.
Making the world better, one answer at a time. the nucleus is made up ofneutrons and protons. on the outside of the nucleus is the electrons. the nucleus is made up ofneutrons and protons. <br/>on the outside of the nucleus is the electrons.
1.9: Understand that atoms consist of a central nucleus, composed of protons and neutrons, surrounded by electrons, orbiting in shells. The nucleus of the atom contains protons and neutrons. The nucleus is orbited by a number of electrons in a number of shells. The following diagram has only one shell of electrons: