19. Which of the following is best classified as a semiconductor of heat/electricity?
a. Silicon
b. Uranium
c. Cesium
d. Helium

If a hydrogen atom is neutral, it must also have  one electron. an oxygen atom (o) has an atomic number of eight (8). this means a neutral oxygen atom has eight protons and eight electrons. the element actium (ac) has an atomic number of 89, so it has 89 protons and 89 electrons in a neutral atom

Bthats what im doing to and i figured it out it is b

They make up examples of physical properties