How do the number of electrons change across the periodic table?

How many moles of lead are in 1.50 x 10^12 atoms of lead? could you explain the answer as well and not just give it to me i am refreshing for finals and i need to know how to do it

What is the chemical formula for dihydrogen monoxide

Match the term to its description match term definition chemical energy a) internal energy caused by vibrations of atoms and molecules electrical energy b) electromagnetic energy that travels in waves radiant energy c) the movement of an electrical charge thermal energy d) potential energy stored in the bonds between atoms