Label the parts of the atom marked.
Atomic number is the number of protons in a nucleus. The mass number is the number of protons plus the number of neutrons. If the atom is neutral the number of protons equals the number of electrons.
Lithium (Li) has 3 protons and (7 – 3 =4) 4 neutrons.
Copy and complete the data table. Atoms are assumed to be electrically neutral.: