Answer:
was difficult to place isotopes of elements as they have the same chemical properties but different atomic masses. It was not possible to predict how many elements could be discovered between two heavy elements as the rise in atomic mass is not uniform.
A cold-blooded animal. Cold-blooded animals can't generate heat themselves so they have to use external sources to keep them warm.
Answer:
Lead atoms have 82 electrons and the shell structure is 2.8. 18.32. 18.4.
Explanation:
The ground state electron configuration of ground state gaseous neutral lead is [Xe].
Ionic bonds usually occur between metal and nonmetal ions. For example, sodium (Na), a metal, and chloride (Cl), a nonmetal, form an ionic bond to make NaCl. In a covalent bond, the atoms bond by sharing electrons. Covalent bonds usually occur between nonmetals.